PROCEEDINGS OF THE UNITED STATES NATIONAL MUSEUM
SMITHSONIAN INSTITUTIONU. S. NATIONAL MUSEUM
Vol. 110 Washington : 1959 No. 3419A DESCRIPTION AND CLASSIFICATION OF THE FINALINSTAR LARVAE OF THE ICHNEUMONIDAE (INSECTA,HYMENOPTERA)
By J. R. T. Short '
IntroductionIn this paper are given a description and classification of the finalinstar larvae of the Ichneumonidae based on a study of species repre-senting 151 genera. Keys are given to the subfamilies, tribes, andgenera. Characters of the subfamilies and tribes are described verbally,but the description of each genus usually takes the form of a diagram.Any special features are noted in the text, and when a species differsfrom that figured for a genus the difference is noted. Diagrams wereselected as the most concise and accurate method for recordinglarval characters. Material and AcknowledgmentsIn work of this nature great care must be taken to insure that onlyreliably identified material is used. Most of the material on whichthis study is based comes from the U.S. National Museum, Wash-ington, D.C. I wish to thank the Museum for permission to borrowmaterial and I am most grateful to Miss Luella M. Walkley for herhelp and advice concerning this work. I am also grateful to Mr. G.
' Natural History Department, Marischal College, University of Aberdeen, Aberdeen, Scotland,391
392 PROCEEDINGS OF THE NATIONAL MUSEUM vol. noStuart Walley of the Canadian Department of Agriculture, Ottawa,for supplying material and to Mr. J. F. Perkins of the British Museum(Natural History) for permission to study material and for his adviceon the classification of the Ichneumonidae. I also wish to thankProf. G. C. Varley of the Hope Department of Entomology, Oxford,for his many helpful suggestions and for lendin'2: me a number of slidesfrom his collection; Mr. E. R. Skinner of the Imperial Forestry Insti-tute, Oxford, who supplied me with larvae of Rhyssa; and Dr. G. Salt,F.R.S., of the Zoological Department, Cambridge University, whosupplied me with larvae of Collyria and Idechthis.Since living larvae often give valuable information, I have collectedas widely as possible for this study. Most of the slide preparationshave been deposited at the U.S. National Museum. Material borrowedfrom the Canadian Department of Agriculture and the British Museumhas been returned. Most of the material sent by Professor Varleyhas been returned, but material of Orthopelma and Hemiteles that hedid not wish returned has been deposited at the U.S. National Mu-seum. Material of Collyria and Idechthis sent by Dr. Salt and materialof Rhyssa sent by Mr. Skinner have also been deposited at the U.S.National Museum. Material returned to the Canadian Departmentof Agriculture (CDA), to the British Museum (BM), and to ProfessorVarley (GCV) is indicated by initials. Material not so indicated hasbeen deposited in the U.S. National Museum.Detailed records (by whom determined, locality, etc.) have notbeen recorded for any specimens since this information can be ob-tained from the data labels of the collections of bred material (nowreturned to the U.S. National Museum and the Canadian Depart-ment of Agriculture) from which larval skins were obtained. Theprocedure adopted in using this bred material was as follows: Thecollection of preparations of larval skins was numbered and fullylabeled; when a larval skin was extracted from the cocoon of a bredspecimen a label was added to the pin of the specimen reading "Larvalskin removed; slide No. X; J.R.T.S.; 195X." Thus, it is possible torefer from the preparation of a larval skin to the adult and its de-termination. MethodsMuch of the material used was available as cast skins in the cocoonsof bred ichneumonids. The contents of the cocoon, the final instarlarval skin and the meconium, were removed by making a longitudinalcut in the cocoon and then boiled in a 5 percent solution of causticpotash. Sometimes larval skins of instars previous to the final werefound in the cocoons. After boiling, the cleaned and softened larvalskins were washed in distilled water, stretched, dehydrated, and
ICHNEUMONID FINAL INSTAR LARVAE SHORT 393mounted in Canada balsam. Balsam was used to ensure a satis-factory permanent mount, but for more rapid work larvae may betransferred from distilled water to Faure's fluid. Where larval mate-rial was available in the host pupa, as in the Ichneumoninae andPimplini, the entire pupa was softened by boiling in caustic potashand the pupa was cut open when soft to extract the ichneumonidlarval skin. This method ensured that the brittle pupa was notnot damaged. Fresh larvae were opened by a midventral cut andthen boiled in a 5 percent solution of caustic potash. They werethen washed, dehydrated, and mounted.NomenclatureThe taxonomy of the Ichneumonidae is in a confused state, and thenomenclature of European and American authors differs to someextent. Since much of the material used in this study is NorthAmerican in origin, the nomenclature of Walkley (1958) is used. Thenames of larvae described in the literature have been altered, whennecessary, to conform with this nomenclature. When genera werenot listed by Miss Walldey, her advice was sought on nomenclature,or, if the genera were listed in Kloet and Hincks (1945), the nomen-clature of these authors was followed.Description and ClassificationSince the relationships indicated by the larval characters supporta classification similar to that given by Townes and Townes (1951)in the U.S. Department of Agriculture's synoptic catalog and byWalkley (1958) in the supplement to that catalog, the classificationof these- authors has been followed. Although a somewhat differentclassification could have been constructed on the basis of larvalstructure alone, every effort was made to avoid this because informa-tion on both larvae and adults is essential for an understanding ofthe taxonomy of the group. A classification based solely on thecharacters of the larvae would be as unsatisfactory as a classificationbased solely on the characters of the adults.It was necessary to depart from the classification in the above-mentioned synoptic catalog in one case: The Anomalinae are hereconsidered as a separate subfamily rather than as a tribe of theOphioninae. Such differences are to be expected since the inde-pendence of larval and adult forms makes a separate evolution possible(Wigglesworth, 1954). Selective factors acting on the legless larvaeare different from those acting on the mobile adults.Studies on larval systematics are of interest from two standpoints;they enable workers to identify larvae and they help in understandingthe classification of the adults (see van Emden, 1957). It is hoped
394 PROCEEDINGS OF THE NATIONAL MUSEUM vol. nothat the keys to subfamilies and tribes will require no great modifi-cation as a result of future work, which is expected to take the formof detailed studies within tribes and genera. As a result of such workthe keys to genera given here will be greatly modified, for the generastudied were usuall}^ represented b}^ but two or three species. Thisnumber of species might be satisfactory if one could assume that thelarval characters of all the species of a genus would indicate a closerelationship. This is ver}^ far from being the case. In some generathis may be due to species differing more as larvae than as adults. Inothers, as in the genus Scamhus, it appears to be due to the confusedstate of the taxonomy of the adults. However, it is hoped that thepresent keys to genera will serve as a basis for future studies.It is generally believed that, since adult insects show a greaterdegree of differentiation than larvae, their characters are likely toremain more important for species identification (van Emden, 1955).No attempt has been made in the present study to give a key tospecies. A vast amount of material would be required for suchwork. But it is significant that species of the braconid genus Apantelescan be arranged into groups corresponding \vith the groups intowhich the adults are divided (Short, 1953).External Structure of Final Instar LarvaThe final instar ichneumonid larva consists of a hemisphericalhead, three thoracic segments, and ten abdominal segments. Thecranium is lightly sclerotized, with the mandibles and certain bandsassociated with the mouthparts more heavily sclerotized. The bodywaU of the thorax and abdomen is very lightly sclerotized or un-sclerotized, with the exception of the spiracles and setae. The spi-racles are situated in most species on the prothoracic and first eightabdominal segments. A line of setae is present in most species encir-cling each thoracic and abdominal segment. Small projections arepresent on the skin and these maj' be lightly sclerotized.The structures used in^this classification are the form of themandibles and head sclerites, and of the antennae, spiracles, andskin. For the basis of the terminology of the head parts, which isoutlined below, reference should be made to Short (1952). Thehead of ichneumonids (fig. 1) is lightly sclerotized except for certainmore heavily sclerotized bands strengthening the cranium in theregion of the mandibles, maxillae, and labium. The sclerotic arch,which is sometimes present dorsal to the mandibles (md), is calledthe epistoma (epst). The anterior tentorial pits (at) are situated inthe epistoma. Lateral to each mandible is a pleurostoma (plst).The mandible articulates with two processes of the pleurostoma (fig.Ic). The anterior pleurostomal process (app) fits into a cavity of
ICHNEUMONID FINAL INSTAR LARVAE^?SHORT 395the mandible and the posterior pleurostomal process (ppp) ends in asocket which receives the mandibular condyle. The hypostoma (fig.1b, list) is a sclerotic band running posteriorly along the subgenalmargin of the cranium. Each maxilla (mx) consists of a lightlysclerotized cardo (cd) and a membranous stipes (st) supportedventrally by a sclerotic band called the stipital sclerite (ss(q)). Themedial lobe of the maxilla represents the lacinia (Ic). The galea isabsent. The maxillary palp (mplp) is reduced to a flattened disc.A sclerotic band called the hypostomal spur (hsp) projects ventrallyfrom the hypostoma across the stipes. In many species it fits intoa depression in the stipital sclerite. Surrounding the posteriormargin of the prelabium (plb) is a labial sclerite (lbs). The labialpalps (Iplp) are reduced to flattened discs. The silk press (sp) atthe orifice (slo) of the silk glands is usually well sclerotized. Someichneumonid larvae, such as the Campopiegini, have a Y-shapedsclerite, called the prelabial sclerite, on the prelabium. A scleroticband, the labral sclerite (1ms), is often present marking the dorsallimits of the labrum (Im).The mandible (fig. Ic) consists fundamentally of a broad base (ba)articulating with the pleurostomal processes, and a more slenderblade (bl). The base and blade of the mandible of Xorides are notdifferentiated, but usually, as for example in the Ephialtini, theblade is slender. The blade of the mandible may bear teeth (t) onits dorsal and ventral surfaces.The antennae (ant) may be papilliform or disc-shaped. Theocular lines (ol), which mark the place of the developing imaginalcompound eyes, are often sclerotized.Each spiracle (fig. Id) consists of a rounded atrium (atr) connectedwith the closing apparatus (ca) by a length of trachea which is oftencharacteristic of the group to which the larva belongs. Finer detailsof spiracular structure have not been used in this classification. Theprothoracic spiracle is usually figm-ed but, where the preparation didnot show the structm-e of this clearl}'^, another spiracle was selectedfor illustration. The proportions of the structure of the spiracles arerelatively constant.The length of the setae of the skin and the presence or absence ofspines have been found useful taxonomic features. Spines serving asholdfast organs are present on the skin of the Polysphinctini and someEphialtini.The drawings of heads which illustrate this paper are morphologi-cally inaccurate since they show it as a flattened object, whereas it is,in reality, a hemisphere. This point is important since Beirne (1941,pp. 149, 167), for example, has attempted to use the position anddegree of curving of the hypostomal sclerite as a taxonomic character.
396 PROCEEDINGS OF THE NATIONAL MUSEUMThis is unwise since the position and degree of cui'ving of the headsclerites depends to some extent on the position assumed duringmounting. However, it has been found a satisfactory method fortaxonomic purposes to record the heads from preparations of castskins and fresh larvae flattened in a standard way. By this methodall the head parts can be shown in the one diagram.The size and appearance of the cocoons have not been used in thisclassification since precise descriptions, either verbally or b}^ drawings,were found very difficult. The color patterns of cocoons should beuseful in future taxonomic work within some genera.pOC pos
Figure 1.-
?
Xorides sp.: a, anterior view of head; b, lateral view of head; c, lateral view ofmandible; d, spiracle. Explanation of symbols on facing page. Detailed explanationon pages 394, 395.
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 397Larval Key to Subfamilies of Ichneumonidae (except Orthocentrinae)L Mandibles unsclerotizcd and, of the head sclerites, only the pleurostoma andeach lateral part of the epistoma are sclerotized: accessory longitudinaltracheal commissure not present CollyriinaeMandibles well sclerotized, or, if not, then labial sclerite present; accessorylongitudinal tracheal commissure present in thorax 22. Labral sclerite present 3Labral sclerite absent ^ 53. Spur of hypostoma meeting stipital sclerite on or near to its median end or,if not, then with each lateral part of labral sclerite broadened into roughlyquadrate area, or with mandible roughly triangular in shape with no cleardifferentiation between base and blade and with two dorsal rows of largeteeth Pimplinae other than Pimplini and AcaenitiniSpur of hypostoma not meeting stipital sclerite close to its median end; eachlateral part of labral sclerite not broadened into quadrate area; mandiblewith blade clearly differentiated from base 44. Epistomal arch lightly sclerotized ^ TryphoninaeEpistomal arch not sclerotized * Cryptinae
2 Except Opheltes, Profarchus (Mesoleiinae, Mesoleiini)
.
3 Except Idiogramma (Tryphoninae, Idiogrammatini).
? Except Oambrus (Cryptinae, Cryptini).
Explanation of Symbols on Figure 1
ama: Anterior mandibular articulationant: Antennaant sk: Antennal socketapp: Anterior pleurostomal processat: Anterior tentorial pitatr: Atrium of spiracleba: Base of mandiblebl: Blade of mandibleca: Closing apparatus of spiraclecd: Cardoclp: Clypeuscs(decl): Coronal stem of dorsalecdysial cleavage linedfm: Cranial depression associated withorigin of frontal musclesepst: Epistomafm: Food meatusfr: Fronsge: Genahyph: Hypopharynxhsp: Sclerotic spur of hypostomahst: Hypostomalb: Labiumlbs: Labial sclerite
Ic: LaciniaIm: Labrum1ms: Labral scleriteIplp: Labial palpmd: Mandiblemplp: Maxillary palpmx: Maxillaoc: Occiputol: Ocular linepa: Parietal region ol craniumplb: Postlabiumplst: Pleurostomapma: Posterior mandibular articulationpoc: Postocciuptpos: Postoccipital sulcusppp: Posterior pleurostomal processprlb: Prelabiumpt: Posterior tentorial pitslo: Salivary orificesp: Silk pressss(q): Stipital scleriteSt: Stipest: Teeth of mandiblevx: Vertex
398 PROCEEDINGS OF THE NATIONAL MUSEUM vol. no
5. Epistomal arch well sclerotized * 6Epistomal arch very lightly sclerotized or absent * 116. Labial sclerite at least moderately sclerotized 7Labial sclerite never more than very faintly sclerotized 107. Labial sclerite complete ventrally 8Labial sclerite incomplete ventrally ' 98. Stipital sclerite and hypostomal spur well sclerotized . Pimplinae, PimpliniStipital sclerite and hypostomal spur very lightly sclerotized.Pimplinae, Acaenitini9. Setae present on prelabium MetopiinaeSetae absent from prelabium ' Anomalinae10. Mandible v.ith grooved blade containing prominent tooth; hypostoma verylightly sclerotized; labial palps not disc-shaped .... OrthopelmatinaeMandible without grooved blade containing prominent tooth; hypostomawell sclerotized; labial palps disc-shaped Ichneumoninae11. Labial sclerite sharply pointed ventrally DiplazoninaeLabial sclerite not sharply pointed ventrally 1212. Mandible with base sclerotized only at periphery MesochorinaeMandible with base evenly sclerotized 1313. Stipital sclerite not extending laterally beyond point of meeting with spur ofhypostoma PlectiscinaeStipital sclerite extending laterally bevond point of meeting with spur ofhypostoma 1414. Mandible with numerous fine teeth on dorsal side of blade . AdelognathinaeMandible not toothed or with short blunt teeth on dorsal and ventral sidesof blade 1515. Hypostoma not extending beyond lateral end of stipital sclerite, or withsclerotic band connecting posterior pleurostomal processes across dorsalsurface of food meatus, or with twelve or more setae situated largely withinthe membrane of the prelabium LissonotinaeHypostoma extending beyond lateral end of stipital sclerite; sclerotic bandnot present connecting posterior pleurostomal processes; if numeroussetae present on prelabium, they are scattered over a very broad labialsclerite as well as over the prelabial membrane 1616. Many (more than four) setae scattered over broad labial sclerite and onmembrane of prelabium Ophioninae, OphioniniNot more than four setae on prelabium 1717. Labial sclerite as wide or wider than long (in anteroposterior direction) andhypostomal spur longer than blade of mandible 18Labial sclerite longer than wide or, if not, then length of hypostomal spuris equal to or less than length of blade of mandible.Ophioninae, Campoplegini18. Mandible conical in shape with small tooth at apex.Ophioninae, TersilochiniMandible not of this shape 1919. Closing apparatus of spiracle not well sclerotized and broader than spiracle.Ophioninae, CremastiniClosing apparatus of spiracle moderately sclerotized and as wide as or morenarrow than spiracle Mesoleiinae
<? E.xcept Listrodromus (Ichneumoninae, Listrodromini), Triclistus (Metopiinae), Xanthopimpla (Pim-plinae, Pimplini).
? Except Exetastes (Lissonotinae)
.
' Except Anomalon (Anomalinae.
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 399In the following descriptions of larval structure in the varioussubfamilies, a list of species studied is given. A list is also given ofthose descriptions in the literature which were thought sufficiently-accurate and detailed to help workers in identifying material. Thestandard of published descriptions of ichneumonid larvae is still poordespite Beirne's (1941) paper, and many references to descriptionshave been omitted since the figures given are too small and vague.The biological notes given for the various subfamilies and tribesare based on those of Townes and Townes (1951) and Walkley (1958).The subfamilies, tribes and genera are considered in the order givenby Townes and Townes (1951), or Walldey (1958), except in the caseof the Mesochorinae, which are moved from a position following theAnomalinae and placed near the Lissonotinae for reasons stated inthe section dealing with the Mesochorinae. The species are consideredin alphabetical order. When genera are added to the list of Walkleythey are placed near what were thought, on larval characters, to beclosely related genera. Subfamily PimplinaeFigures 2-10On larval characters the Pimplinae fall into two groups; in one arethe Pimplini and in the other are the Ephialtini, Polysphinctini,Neoxoridini, Rhj^ssini, Theroniini, Labenini, and Xoridini. TheAcaenitini have a special position. The Pimplini usually have theepistoma well sclerotized, the hypostoma short, and the mandiblelarge and without teeth. The labial sclerite is longer than wide andits ventral side is broad. The labral sclerite is absent. The setae onthe skin are small. In the second group the epistoma is, at most,lightly sclerotized, and the hypostoma is long. The mandibles arerelatively smaller than in the Pimplini and they usually bear teeth.The form of the mandible is similar in the Ephialtini, Neoxoridini,Rhyssini, and Labenini in having a slender blade and a dorsal andventral row of small teeth. In the Theronimi and in Delomerista(Ephialtini) the blade of the mandible is bifurcated, one part havingdorsal and ventral teeth and the other being toothless. The labialsclerite is basically triangular in shape, although in the Rhyssini andNeoxoridini the labial sclerite is pointed ventrally, and in the Theroni-ini the ventral part of the labial sclerite is broad so that the scleriteresembles that of the Pimplini and Acaenitini. The labral sclerite ispresent. The setae on the skin are relatively longer than in the firstgroup. The Acaenitini show characters of both groups. The man-dible is similar to that of the Pimplini, and the absence of the labralsclerite and the presence of a sclerotized epistoma also suggest this
400 PROCEEDINGS OF THE NATIONAL MUSEUM vol. no
tribe. But the hypostoma is long and the labial sclerite is roughlytriangular in shape, although the ventral part of the sclerite is broadas in the Pimplini. In all tribes of the Pimplinae, with the exceptionof the Labenini and Xoridini, the hypostomal spur meets the stipitalsclerite on or near the point of meeting of this and the labial sclerite.In the Pimplini this results in the sclerites around the mandibleshaving a ringlike appearance. Apart from this one character thegroups in the Pimplinae are distinct.Since the Pimplini (with the possible exception of Itoplectis) areendoparasites which emerge from the pupa of the Lepidopterous host,and the remaining tribes of the Pimplinae (with the possible exceptionof some Acaenitini) are ectoparasites, differences in larval structuremight be expected. The Pimplini, with their large, toothless man-dibles and well-developed epistomal and pleurostomal sclerites resembleto some degree other ichneumonid larvae with similar habits (seepp. 502,505,506).Beirne (1941) in his classification of larval Ichneumonidae hasplaced the Polysphinctini, Rhyssini, Ephialtini, and Xoridini with theCryptinae. This has not been followed in the present study for,although the Pimplini differ in many aspects from the Ephialtini andsimilar tribes, the position of the hypostomal spur gives a commoncharacter for the subfamily. Where this character is not shownclearly, as in the Labenini and Xoridini, the remaining charactersindicate the relationships of the tribe. In the Labenini the form ofthe mandible closely resembles that of the Ephialtini. In the Xoridinithe general form of the head sclerites, particularly the labial sclerite,resembles that of most Pimplinae, rather than any other Ichneumonidgroup. The form of the mandible of the Xoridini differs from that ofall other ichneumonids.It is significant that the Acaenitini and Theroniini show charactersresembling those of both the Pimplini and the Ephialtini and similartribes. Larval Key1. Setae on body longer than blade of mandible PolysphinctiniSetae on body not longer than blade of mandible 22. Labial sclerite sharply pointed ventrally 3Labial sclerite not sharply pointed ventrally 43. Ventral point of labial sclerite continuous with sclerite RhyssiniVentral point of labial sclerite appearing as distinct plate at end of sclerite.Neoxoridini4. Each lateral part of labral sclerite expanded into quadrate-shaped area.LabeniniEach lateral part of labral sclerite not expanded into quadrate-shaped area . 5
ICHNEUMONID FINAL INSTAR LARVAE SHORT 401
5. Ventral part of labial sclerite broad and without lobes on ventral surface.TheroniiniVentral part of labial sclerite, if broad, has lobes on ventral surface ... 66. Mandible triangular with no sharp differentiation between base and blade.XoridiniMandible with sharp differentiation between base and blade . . EphiaJiiniTribe EphialtiniFigures 2-4The epistoma is absent except in Tromatohia where it is present asa thin, hghtly sclerotized arch; the pleurostoma is lightly sclerotized;the hypostoma is well sclerotized and may be enlarged posterior tothe hypostomal spur; the spur of the hypostoma meets the stipitalsclerite at its point of meeting the labial sclerite; the stipital scleriteis always present but it may be short; the cardo is visible in somegenera as a lightly sclerotized plate; the labial sclerite is roughlytriangular in shape; the labral sclerite is present and its median partis lightly sclerotized and often bilobed; the mandible in most generahas a slender blade with a row of fine teeth on the dorsal and on theventral surfaces (but Tromatohia appears to have only a dorsal rowof teeth, and in Delomerista di'prionis Cushman the blade is bifurcated)
;
the antenna is papilliform; the closing apparatus of the spiracle isnarrower than the atrium and is usually separated from the atriumby a length of trachea equal in length to that of the closing appa-ratus, although in Alophosternum the closing apparatus is long andslender; the skin has well developed setae which are usually equalin length to the blade of the mandible; in Tromatohia the setae arevery small and groups of spines are present; spines are absent fromother genera of the tribe. Larval Key
1. Small lobes present on ventral edge of labial sclerite ^ 2Small lobes not present on ventral edge of labial sclerite 32. Hypostomal spur as broad as or broader than posterior part of hypostoma.Calliephialtes, EphialtesHypostomal spur more narrow than posterior part of hypostoma . . Scambus3. Mandible with blade bifurcated 8 DelomeristaMandible with blade not bifurcated 44. Enlargement present on posterior part of hypostoma IseropusEnlargement not present on posterior part of hypostoma 55. Slender epistomal arch present TromatobiaEpistomal arch absent Alophosternum
' Except Scambus pomorum (Ratzeburg) (Imms, 1918; Speyor, 1920) and Calliephialtes dimorphus Cush-man (Sauer, 1939).
' Except Delomerista sp. (Morris, Cameron and Jep.son, 1937).
402 PROCEEDINGS OF THE NATIONAL MUSEUM
,i^.^^?^-^^fi-^?O'l mm
Figure 2.?Pimplinae-.Ephialtini, head sclerites: a, Scamhus hispae (Harris); b, Alophos-ternum foliicola Cushman; c, Calliephialtes variatipes (Provancher). (1, antenna; 2,spiracle; 3, skin.)
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 403
Figure 3.?Pimplinae:Ephialtini, head sclerites: a, Ephialtes irritaior (Fabricius); b,Iseropus stercorator brunneifrons (Viereck); c, Tromatobia rujopectus (Cresson). (1,antenna; 2, spiracle; 3, skin.)
404 PROCEEDINGS OF THE NATIONAL MUSEUM
FiGURK 4.?Pimplinae:Ephiakini, head sclerltes: Delomerisia diprionis Cushman. (1,antenna; 2, spiracle; 3, skin.)The above key must be regarded as provisional, for, on the presentmaterial, it is very difficult to decide on any one characteristic of agenus. This may be due to the fact that Scamhus, to take one exam-ple, is a composite genus. Dr. G. S. Walley (in litt.) has reached sucha conclusion on Scamhus from study of the adults.Genus Scamhus.?S. hispae (Harris) has been examined (fig. 2a).S. hrevicornis (Gravenhorst) is figured hj Thorpe (1930), S. detritus(Holmgren) by Salt (1931), S. foliae (Cushman) by Dowden (1941),and S. pomorum. (Ratzeburg) by Imms (1918) and by Speyer (1926).S. pomorum has neither lobes on the ventral surface of the labialsclerite nor an enlargement on the hj-postoma as has aS'. hispae. S.hrevicornis, S. foliae and S. detritus have lobes on the ventral surfaceof the labial sclerite, but an enlargement is not present on the hypo-stoma. The ventral surface of the labial sclerite of S. detritus is morepointed than in other species. These points are of interest sinceTromera pomorum (Ratzeburg) and Epiurus hrevicornis (Gravenhorst)are type species of genera sjmon^'^mized under Scamhus.Genus Alophosternum.?A. foliicola Cushman has been examined(fig. 2b). The closing apparatus of the spiracle of this genus differsfrom others of the tribe in its long slender shape (fig. 2B2).Genus Calliephialtes.?C. nuhilipennis (Viereck) and C. variatipes(Provancher) (fig. 2c) have been examined. Both species possess
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 405lobes on the veutral surface of the labial sclerite, which isslightly pointed. The more posterior part of the hypostoma isslightly enlarged in C. variatipes but not in C. nuMlipennis. Thebody setae are conspicuously large in C. nubilipennis. C. dim.orphusCushman is figured by Sauer (1939) and lobes do not appear to bepresent on the ventral surface of the labium, although the figure istoo small to show the head structures clearly.Genus Ephialtes.?E. irritaior (Fabricius) has been examined (fig.3a). E. elegans (Woldstedt) is figured by Beirne (1942a), E. mani-iestor (Linnaeus) by Baumann (1933), E. punctulatus Ratzeburg b}^Beirne (1941) and Rosenberg (1934), and E. rvficollis (Gravenhorst)by Thorpe (1930). All these species have numerous lobes on theventral surface of the labial sclerite.Genus Iseropus.?The species of this genus are gregarious. /.califortiicus Cushman and /. stercorator brurmeifrons (Viereck) (fig.3b) have been examined. The enlargement of the hypostoma is m.oremarked in /. californicus than in /. stercorator brunneifrons. I.stercorator stercorator (Fabricius) is figured by Beirne (1941).Genus Tromatobia.?Species of this genus parasitize the eggcocoons of spiders. T. rufopectus (Cresson) (fig. 3c) and T. zonata(Davis) have been examined. The head sclerites are slender withno lobes on the ventral surface of the labium and no enlargement ofthe hypostoma. A slight epistoma is visible and teeth appear to bepresent only on the dorsal surface of the mandible. Maneval (1936)notes the presence of groups of large hooked spines on the dorsalsurface of the first seven abdominal segments of Zaglyptus varipesvaripes (Gravenhorst). Similar spines are present on the abdomenof Tromatobia (fig. 3C3). These spines, which appear to be holdfastorgans, closely resemble the body spines of the Polysphinctini. LikeTrombatobia and Zaglyptus, the Polysphinctini are parasites of spiders.Genus Delomerista.?The species of this genus are parasites of thecocoons of sawflies. D. diprionis Cushman has been examined(fig. 4a). The bifurcate mandibles may be distinctive of this genus.Morris, Cameron, and Jepson (1937) figure Delomerista sp., where themandible appears to have the same shape as that of other Ephialtiniand a more or less complete epistoma is present. It is unfortunatethat the identification was not taken further.Tribe PolyspbinctiniFigure 5The members of this tribe are parasites of spiders.The setae on the head and body are conspicuously long, the setaeon the bod}^ being at least as long as the blade of the mandible; thedorsal part of the epistoma is not sclerotized and the pleurostoma is
406 PROCEEDINGS OF THE NATIONAL MUSEUM
0-1 mmFigure 5.?Pimplinae:Polysphinctini, head sclerites: a, Hymenoepimecis sp.; b, Oxyrrhexiscarbonator texana (Cresson); c, Zatypota sp., antenna not visible on preparation. (1,antenna; 2, spiracle; 3, skin.)
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 407lightly sclerotized ; the hj^postoma is well sclerotized and in Oxyrrhexisand Acrodactyla (Beirne, 1941) is expanded at the posterior end;the hypostomal spur is well sclerotized, as is the stipital sclerite whichis expanded at its posterior end in Hymenoepimecis and Oxyrrhexis;the labial sclerite is roughly square in shape in Zatypota but roughlytriangular in other genera, although the ventral part of the scleriteis pointed in Zatypota and Acrodactyla; the maxillary and labialpalps each have one sensillum in Hymenoepimecis, Oxyrrhexis andAcrodactyla, but there are two sensilla to each palp in Zatypota;the labral sclerite is lightly sclerotized in its lateral parts but isunsclerotized dorsally; the mandible is slender and small teeth arepresent on the dorsal surface of the blade ; the antenna is papilliform
;
the closing apparatus of the spiracle is close to the atrium ; long setaeare present on the skin; spines, which appear to serve as holdfastorgans, are present on the dorsal surface of some body segments. Itis not possible to distinguish the precise distribution of these spinesfrom cast skins. Nielsen (1923, 1935, 1936) figures and describesthe distribution of these spines in the tribe but gives no adequatefigure of the head structure of the larvae.Larval Key
1. No enlargement present on posterior part of hypostoma . . HymenoepimecisEnlargement present on posterior part of hypostoma 22. Lateral end of stipital sclerite expanded OxyrrhexisLateral end of stipital sclerite not expanded . '. ... 33. Ventral part of labial sclerite with small dorsal projection into prelabialarea ZatypotaVentral part of labial sclerite without dorsal projection .... AcrodactylaThe following have been examined: Hymenoepimecis sp. (fig. 5a),Oxyrrhexis carbonator texana (Cresson) (fig. 5b), and Zatypota sp.(fig. 5c). Acrodactyla degener (Haliday) is figured by Beirne (1941).Tribe PimpliniFigures 6, 7The members of this tribe are endoparasites of a variety of lepi-dopterous pupae.The head sclcrites are distinctive in that they appear to form aring around the mouth. The epistoma is well sclerotized, except inXanthopimpla; the pleurostoma is well sclerotized and the hypostomais short in most species; the hypostomal spur is well sclerotized andthe stipital sclerite is short in most species; the labial sclerite is longerthan wide with thin lateral parts and a broadened ventral part;the mandible is relatively large and has no teeth on the blade; thelabral sclerite is absent and in some genera the sensilla of the labrum504675?59 2
408 PROCEEDINGS OF THE NATIONAL MUSEUM
0-1 mm
O-Imm 3Figure 6.?Pimplinae:Pimplini, head sclerites: a, Pimpla aequalis Provancher, antennanot visible on preparation; b, Apechthis compunctor (Linnaeus). (1, antenna; 2, spiracle;3, skin.)
ICHNEUMONID FINAL INSTAR LARVAE?SHORT . 409
Figure 7.?PImplinae:Pimplini, head sclerites: a, Xanthopimpla stemmator (Thunberg);B, Itoplectis behrensii (Cresson); c, Echihromorpha notulatoria (Fabricius). (1, antenna;2, spiracle; 3, skin.)
410 PROCEEDINGS OF THE NATIONAL MUSEUM vol. no
are grouped on certain raised areas ; the hypopharynx has numeroussmall spine-like projections; the antenna is disc-shaped with thecircumference lightly sclerotized in some genera, and several sensillamay be visible in the central part of the antenna; the atrium of thespiracle is broad and shallow and the closing apparatus is close to theatrium; the skin is relatively smooth and has smaU setae.Larval Key
1. Hypostomal spur with lightly sclerotized lateral expansion . . XanthopimplaHypostomal spur without lightly sclerotized lateral expansion 22. Hypostoma approximately equal in length to blade of mandible . ApechthisHypostoma much shorter than blade of mandible 33. Stipital sclerite much shorter than blade of mandible ItoplectisStipital sclerite approximately equal in length to blade of mandible ... 44. Broadened (ventral) part of labial sclerite about as broad as long and notpointed ventrally PimplaBroadened (ventral) part of labial sclerite longer than wide and pointedventrally EchthroniorphaGenus Pimpla.?P. aequalis Provancher (fig. 6a) and P. inflatusTownes have been examined. P. instigator (Fabricius) is figured byBeirne (1941) and by Meyer (1922), P. luctunosa Smith by Itawa(1950), P. turionellae (Linnaeus) by Thorpe (1930), Silvestri (1941),and Beirne (1943), and Pimpla sp. by Beirne (1942).Genus Apechthis.?A. coinpunctor (Linnaeus) (fig. 6b) has beenexamined. This species is figured by Beirne (1941).Genus Itoplectis.?^The species of this genus may be primary orsecondary parasites. Professor Varley (in litt.) informs me that/. maculator (Fabricius) appears to be more often a primary parasiteon Tortrix and other species, although sometimes a secondary para-site. /. hehrensii (Cresson) (fig. 7b) and /. conquisitor (Say) havebeen examined. /. alternans (Gravenhorst) is figured by Morris,Cameron, and Jepson (1937), /. olivalis Thomson by Beirne (1941),and Itoplectis sp. by Snodgrass (1935). Morris, Cameron, and Jepson(1937) state that the inner aspects of the teeth of /. alternans arearmed with bristles. Teeth have not been recorded on the blade ofthe mandible in any other species of this tribe. These authors studiedthis species as a primary parasite of Diprion. It oviposited on pre-pupae and pupae within the host cocoon and fed externally. Allother genera of the Pimplini appear to be endoparasites.Genus Echthromorpha.?E. insidiator (Smith) and E. notulatoria(Fabricius) (fig. 7c) have been examined. E. formosa (Smith) isfigured by Beirne (1941).Genus Xanthojnmpla.?The broad and lightly sclerotized hyposto-mal spur and the lightly sclerotized epistoma are characteristic of thisgenus. The stipital sclerite is short and fused with the hypostomal
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 411
spur. X. cera (Cameron), X. enderleini Knieger, and X. stemmator(Thunberg) (fig. 7a) have been examined. X. pedator (Thomson),figured by Beirne (1941), differs from other species of the genus inthat the lateral parts of the labial sclerite are very broad; however,the hypostomal spur and the stipital sclerite appear to be similar tothose of other species. X. citrina (Holmgren) is figured by Moutiaand Courtois (1952). Tribe NeoxoridiniFigure 8aThe only species of this tribe examined was Neoxorides horealis(Cresson) (CDA) (fig. 8a). Members of this genus are parasites ofwood-boring Coleoptera.The dorsal part of the epistoma is unsclerotized but the pleurostomaand hypostoma are well sclerotized; the hypostomal spur has a broaddorsal part but narrows ventrally where it fuses with the narrowstipital sclerite; the lateral end of the stipital sclerite is Y-shaped; theventral part of the labial sclerite is broad and pointed, although thepoint appears as a separate cap on the remainder of the labial sclerite
;
the maxillary and labial palps each have two sensilla, one round andone crescentic in shape; only the lateral parts of the labral sclerite arewell sclerotized; the mandible has a slender blade and a dorsal andventral row of small teeth, thus resembling the mandibles of theEphialtini, Rhyssini and Labenini; the antenna is papilliform; theatrium of the spiracle is funnel-shaped and the closing apparatus isclose to the atrium; the skin has setae of moderate size but no spines.Tribe RhyssiniFigure 8bSpecies of this tribe parasitize wood-boring Coleoptera and sawflies.The only specimen examined was Rhyssa sp. (fig. 8b).The dorsal part of the epistoma is not sclerotized and the pleuro-stoma is lightly sclerotized; the hypostoma and hypostomal spur arewell sclerotized and the hypostomal spur is broad at its dorsal end;the stipital sclerite is well sclerotized and is broad at its lateral end;the labial sclerite is sharply pointed ventrally; the maxillary andlabial palps each have two sensilla, one round and one crescentic; thedorsal part of the labral sclerite is not sclerotized; the mandible has aslender blade with a dorsal and ventral row of small teeth; there is asmall, lightly sclerotized plate on the clypeus; the antenna is papil-liform; the atrium of the spiracle is funnel-shaped and the closingapparatus, which has relatively thick walls, adjoins the atrium; theskin has setae of moderate size but no spines.Rhyssa sp. is figured by Beirne (1941).
412 PROCEEDINGS OF THE NATIONAL MUSEUM
Figure 8.?Pimplinae, head sclerites: a, Neoxorides borealis (Cresson) (Neoxoridini); b,Rhyssa sp. (Rhyssini). (1, antenna; 2, spiracle; 3, skin.)
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 413Tribe TheroniiniFigure 9aThe only species examined was Theronia atalantae (Poda) (fig. 9a),The species of Theronia are usually primary and secondary parasitesof the pupae of Lepidoptera.The dorsal part of the epistoma is unsclerotized and the pleurostomais lightl}^ sclerotized; the hypostoma and hypostomal spur are slenderand well sclerotized; the stipital sclerite is lightly sclerotized and avery lightly sclerotized cardo is present; the lateral parts of the labialsclerite are slender and well sclerotized and the ventral part is broadand lightly sclerotized ; each maxillary and labial palp has two sensilla,one round and one crescentic in shape; the labral sclerite is present;the mandible has a broad base and the blade is bifurcated with onepart bearing dorsal and ventral teeth and the other, which projectsposteriorly, being toothless; the antenna bears a small papillus; theclosing apparatus of the spiracle has slender walls and adjoins theatrium; the skin bears setae approximately equal in length to that ofthe toothed part of the blade of the mandible and has no spines.The mandible and the labial sclerite of the final instar larva of T.atalantae are figured by Meyer (1922).Tribe LabeniniFigure 9bThe only species examined was Labena grallator (Say) (fig. 9b).Species of the genus Labena parasitize wood-boring Coleoptera.The dorsal part of the epistoma is very faintly sclerotized; thepleurostoma is well sclerotized and has a lightly sclerotized lateralexpansion; the hypostoma is well sclerotized and has a lightlysclerotized posterior expansion; the hypostomal spur is well sclerotized;the stipital sclerite is V-shaped with its lateral part expanded andcurved dorsally; the labial sclerite is similar in shape to that of manyEphialtini, but there are no lobes on the ventral surface; on eachmaxillary and labial palp there are two sensilla, both round and onesmaller than the other; the labral sclerite is distinctive with eachlateral part bearing a quadrate-shaped expansion and the median(dorsal) part being unsclerotized except for a small, lightly sclerotizedplate; the antenna is papilliform; the atrium of the spiracle is oval inshape and the closing apparatus is thick-walled and situated close tothe atrium; the skin has setae of moderate size but no spines.
414 PROCEEDINGS OF THE NATIONAL MUSEUM vol. no
/ -
Figure 9.?Pimplinae, head sclerites: a, Theronia atalantae (Poda) (Theronlini); b, LahenagrallatoT (Say) (Labenini). (1, antenna; 2, spiracle; 3, skin.)
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 415Tribe XoridiniFigure 10aSpecies of this tribe parasitize wood-boring Coleoptera.Xorides insularis (Cresson) and X. rileyi (Ashmead) (fig. 10a) havebeen examined.In the genus Xorides the dorsal part of the epistoma is not scle-rotized, but the pleurostoma, hypostoma, hypostomal spur, andstipital sclerite are well sclerotized; the labial sclerite is roughlytriangular in shape; the maxillary and labial palps each bear twosensilla, one round and one cresccntic in shape; the labral scleritein both species examined does not have the dorsal part sclerotizedand each lateral part consists of two sclerotic bands which join ven-trally; the mandible is distinctive with a broad blade bearing two rowsof large teeth on the dorsal surface ; the antenna is papilliform ; thespiracular atrium is oval in shape and the closing apparatus is closeto the atrium; small setae but no spines are present on the skin.Ischnoceros rusticus (Geoffroy) is figured by Berine (1941), Xori-descopus sp. by Ayyar (1943), X. brachylahris (Kriechbaumer) byChrystal and Skinner (1931), Xorides praecatorius (Fabricius) byBeirne (1941), and Xorides sp. by Short (1952). All specimens de-scribed in the literature appear to have the labral sclerite consistingonly of a single sclerotic band and not double as in the species figuredin the present paper. Chrystal and Skinner show small lobes on theventral surface of the labial sclerite of X. brachylahris. The labiumthus resembles those of some Ephialtini. These authors also recordthat there is no striking difference between the larva of this speciesand that of X. irrigator (Fabricius) which they also examined. Theselobes have not been recorded on the labium of any other species ofthis tribe, although Ayyar figures what appears to be a sclerotic platebeneath the ventral surface of the labial sclerite in Xoridescopus . Itis unfortunate that this figure is poor and on bad paper.Tribe AcaenitiniFigure 10bMembers of this tribe are parasites of wood-boring Coleoptera.The only species of this tribe examined was Arotes formosus Cresson(fig. 10b). Cushman and Rohwer (1921, p. 392) state that the groupis ectoparasitic. The complete epistoma, toothless mandible andsmall skin setae of Arotes suggest that it is an endoparasite, althoughthe larval characters of Coleocentrus , as figured by Baumann (1933),suggest that this genus is an ectoparasite.
416 PROCEEDINGS OF THE NATIONAL MUSEUM
0-1 mm
Ot mmFigure 10.?Pimplinae, head sclerites: a, Xorides rileyi (Ashmead) (Xoridini); b, Arotesformosus Cresson (Acaenitini), antenna not visible on preparation. (1, antenna; 2,spiracle; 3, skin.)
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 417It has been already noted that the Acaenitini have characterssimilar to those of the two groups of the Pimplinae, the Ephialtiniand similar tribes, and the Pimplini.In the genus Arotes the epistoma and pleurostoma are moderatelysclerotized and broad; the hypostoma is moderately sclerotized butvery slender; the hypostomal spur is broad and very lightly sclerotized
;
the stipital sclerite is short, broad and very lightly sclerotized; thelabial sclerite is roughly triangular in shape, but the ventral part ismuch broader than the lateral parts as in the Pimplini ; the maxillarypalps each bear one large, round sensillum and a group of smallersensilla; each labial palp bears one large round sensillum and onesmall sensillum; the labral sclerite is absent and there are two prom-inent groups of sensilla on the labrum; the mandibles resemble thoseof the Pimplini in having a large blade and no teeth; the antennaewere not visible on the specimen; the spiracular atrium is oval, andthe closing apparatus, which is relatively long and with thin walls,is situated adjacent to the atrium; the skin has very small setae butno spines.Coleocentrus excitator (Poda) is figured by Baumann (1933). Theantenna of this species appears to be disc-shaped. The epistomaappears to be incomplete, but the figure given is too small to makethis point clear. Subfamily AdelognathiiiaeFiGUKE 11aMembers of this subfamily are gregarious external parasites onsawfly larvae. Adelognathus and related genera have been placedas a tribe of Tryphoninae by some authors. In the present study itwas found necessary to consider this group as a subfamily since theform of the mandible, the absence of an epistoma and a labral sclerite,the presence of a prelabial sclerite and of a clearly papilliform an-tenna '^ and the absence of spines on the skin all separate Adelognathusfrom other genera of the Tryphoninae. I have been unable to dis-cover whether Adelognathus possesses the stalked egg that is charac-teristic of the Tryphoninae. The ovaries of an adult were examinedand the eggs present did not appear to be stalked.Adelognathus britannicus Perkins (GCV), A. pallipes (Gravenhorst)(GOV) and Adelognathus sp. (GCV) were examined.The dorsal part of the cranium is sufficiently sclerotized to appeardark; the epistoma is unsclerotized except for small projections above
"? A papilliform anteima is present in Hybophanes scabriculus (Gravenhorst) and Phptodietus pulcherrimus(Cresson) (Simmonds, 1947) of the Tryphoninae. The antenna was not visible in the specimen of P.pulcherrunus examined in the present study. In the remainder of the Tryphoninae the antenna is notpapilliform, although a relatively large, rounded sensillum may be present in the middle of the disc-shapedantenna as in Idiogramma.
418 PROCEEDINGS OF THE NATIONAL MUSEUM
OI m m
Oi mm
I 10-1mmFigure 11 -Head sclerites : //<i./ogna;/m. palHpes (Gravenhorst) (Adelognathinae) ; b,Phytod^etus pulcherrinuu (Cresson) (Tryphoninae:Phytodietini),
-^^^.^^^^'f';. ^^^preparation; c, NeUlia geminatus (Say) (Tryphoninae-.Phytodietm,). (1, antenna, 2,spiracle; 3, skin.)
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 419the anterior pleurostomal processes; the pleurostoma is hghtly scler-otized; the hypostoma, hypostomal spur and stipital sclerite are wellsclerotized; the labial sclerite is well sclerotized and the lateral partsmeet the ventral almost at right angles; a prelabial sclerite is present;each maxillary and labial palp bears two sensilla, one round andone crescentic in shape; the mandibles are distinctive, being largewith a long broad blade having a row of fine teeth on the dorsal edge
;
the labral sclerite is absent; the antenna is papilliform; the closingapparatus of the spiracle is long and slender and is separated from theatrium by a length of trachea equal in length to the atrium ; the skinbears small setae but no spines; small bubble-like projections arepresent on the skin, but these are not pointed and sclerotized as inthe Tryphoninae and cannot be called spines.Beirne (1941) figures Adelognathus sp. indescr.Subfamily TryphoninaeFigures 11b-13dMembers of this subfamily are ectoparasites and the tribes areclosely related. The eggs are attached to the skin of the host by astalk (by other structures in some Cteniscini) and the parasite larvacompletes its development in the host cocoon.The head sclerites are all well developed, although the epistoma isonly slightly sclerotized in the Phytodietini and the prelabial scleriteis absent; the mandibles are of moderate size and may bear teeth onthe dorsal edge of the blade or teeth may be absent; the antenna isdisc-shaped with one to tliree sensilla in the center; the closing ap-paratus of the spiracle is slender and is situated some distance fromthe atrium, except in Netelia where the closing apparatus is as broadas the atrium and adjoins the atrium; large setae and small spinesa-re present on the skin, except in Exenterus where the spines areconspicuously large and are about half as long as the setae.Larval Key
1. A lightly sclerotized plate is present on the labium ventral to the labial sclerite.PhytodietiniA lightly sclerotized plate is not present on the labium ventral to the labialsclerite 22. Dorsal part of epistoma unsclerotized IdiogrammatiniDorsal part of epistoma sclerotized 33. Labial sclerite slender with width much less than that of stipital sclerite.BoethiniLabial sclerite relatively broad with width approximately equal to that ofstipital sclerite 4
420 PROCEEDINGS OF THE NATIONAL MUSEUM vol. no
4. Mandible without teeth; setae on body with length equal to one-third to one-half that of mandible CtenisciniMandible with teeth," or, if without teeth, then setae on body large with lengthequal to approximately three-quarters that of mandible 55. Mandible with teeth; maxillary and labial palps each with three sensilla, or,if not, then with two sensilla, one round and one crescentic . . ThymaridiniMandible without teeth, or, if with teeth, then maxillary and labial palps eachwith two sensilla both of which are round TryphoniniTribe PhytodietiniFigure 11b,cThe members of this tribe are parasites of caterpillars. The egg isattached to the host b}^ a stalk and most of the larval developmentoccurs after the host spins its cocoon or makes a pupal cell in theground.The lightly sclerotized plate situated on the labium ventral to thelabial sclerite is characteristic of this group. In contrast to the othertribes of the subfamily the dorsal part of the epistoma is very lightlysclerotized. Larval Key
1. Closing apparatus of spiracle narrow and separated from atrium by a lengthof trachea equal to length of closing apparatus PhytodietusClosing apparatus of spiracle broad and situated adjacent to atrium . NeteliaPhytodietus pulcherrimus (Cresson) (fig. 11b), Netelia exserta (Cusli-man), and A^^. geminatus (Say) (fig. lie) have been examined.The labral sclerite of A^. exserta differs from that of A^. geminatusin that the dorsal part consists only of a single sclerotic band and thelateral parts do not end in forked enlargements. This is of interestsince Townes and Townes (1951) place exserta in the subgenus Pros-thodocis, whereas geminatus is placed in the subgenus Netelia.There is a relatively large, round sensillum in the center of theantenna in Netelia. The sensillum is, however, much smaller thanthe papillus of a papilliform antenna, and the antenna of Netelia isbest described as disc-shaped.Phytodietus pulcherrimus (Cresson) is figured by Simmonds (1947),and P. gelitorius (Thunberg) and Netelia vinulae (Scopoli) are figuredby Beirne (1941). Simmonds does not figure the sclerotized plate onthe labium of P. pulcherrimus. This is presumably an oversight.Beirne describes a lower row of small teeth near the tip of the bladeof the mandible in Netelia. This row of teeth was not seen in thespecies of Netelia examined.
" Teeth are present on the mandible of Erromenus dolichops Townes and Townes (Tryphonini) but theyare very small. This species (flg. 13a) may be distinguished from the Cteniscini by the shape of themandible.
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 421Tribe Thymaridini (=Eclylini)Figure 12a,
b
Members of this tribe are parasitic mostly on small Lepidoptera.Eclytus omatus Holmgren is a parasite of Tenthredinidae.The species examined were E. omatus Holmgren (CDA) (fig. 12a),E. pleuralis (Provancher) (CDA), Hyhophanes scahriculus (Grav-enhorst) (GCV) (fig. 12b), and Neliopisthus elegans (Ruthe) (GCV).All the head sclerites are present with the exception of the prelabialand the dorsal part of the labral sclerite is absent in Hyhophanes andNeliopisthus; the epistomu is slender in Eclytus but relatively broad,although lightly sclerotized, in Hyhophanes and Neliopisthus; the lat-eral parts of the labial sclerite meet the ventral almost at riglit anglesin Eclytus but the ventral part of this sclerite is rounded in Hyhophanesand Neliopisthus; in Hyhophanes and Eclytus omatus each maxillaryand labial palp has three sensilla, one large, one small and one minute,but in E. pleuralis each palp has two sensilla, one round and one cres-centic; the mandible has a prominent row of teeth on the dorsal sur-face of the blade; the closing apparatus of the spiracle is small andthe length of trachea which separates it from the atrium is twice aslong as the closing apparatus in Eclytus and three times as long inHyhophanes and Neliopisthus; the setae on the skin are prominent,especially in Hyhophanes and Neliopisthus, and there are small spines.Eclytus fontinalis Holmgren is figured by Beirne (1941).Larval Key
1. Setae on skin of thorax equal in length to blade of mandible .... EclytusSetae on skin of thorax as long as or longer than hypostonria 22. Epistoma sharply arched HyhophanesEpistoma not sharply arched NeliopisthusTribe IdiogrammatiniFigure 12cIdiogramma sp. was examined. The species of this genus areparasitic on the larvae of Xyela feeding in the staminate cones ofPinus. Idiogramma is an isolated genus showing no close resem-blance to other Tryphoninae.The dorsal part of the epistoma is unsclerotized ; the pleurostomais very lightly sclerotized; the hypostoma, hypostomal spur, stipitalsclerite and labial sclerite are moderately sclerotized; each maxillaryand labial palp has two sensilla; there is no prelabial sclerite; the silkpress is very lightly sclerotized; a labral sclerite is present; the man-dibles are distinctive in shape, each having a somewhat square baseand a curved toothless blade; the antenna has a large central sensillum
422 PROCEEDINGS OF THE NATIONAL MUSEUM
--M.~-kiL^?Ol m mFigure 12.?Tryphonlnae, head sclerites: a, Eclytus ornatus Holmgren (Thymaridini),antenna not visible on preparation; b, Hybophanes scahriculus (Gravenhorst) (Thymari-dini), with skin showing prothoracic setae and spines; c, Idiogramma sp. (Idiogrammatini).(1, antenna; 2, spiracle; 3, skin.)
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 423but is not clearly papilliform; the closing apparatus of the spiracleis separated from the atrium by a length of trachea approximatelyequal to the depth of the atrium; the skin bears small setae and spines.It is possible that Idiogramma should be placed in a subfamilyof its own since the shape of the mandible and the incomplete epistomaseparate this genus from other Tryphoninae. However, since theepistoma is partly sclerotized dorsal to the anterior tentorial pits, alabral sclerite is present, the antenna is not papilliform, and theeggs are stalked, the genus has been placed with the Tryphoninae.The structure of the spiracles and the presence of distinct spines on theskin are characteristics similar to those of many Tryplioninae. Thecharacters of Idiogramma do not resemble those of any other sub-family of the Ichneumonidae.Tribe BoethiniFigure 13aBoethes sp. was examined. Members of this genus are parasitic onthe larvae of argid sawflies.All the head sclerites are present with the exception of the prelabial;the labial sclerite is slender and its lateral parts meet the ventralalmost at right angles; each maxillary and labial palp bears twosensilla, both round and one large and one small; two groups each offour sensilla are present on the labrum; the mandibles are withoutteeth; the antenna is disc-shaped with a prominent sensillum in thecenter; the length of trachea separating the closing apparatus of thespiracle from the atrium is almost equal to that of the closing appara-tus; the skin bears large setae and small spines.Tribe TryphoniniFigure 13b,
c
Members of this tribe are parasites of the larvae of Tenthredinidae.Polyblastus pedalis (Cresson) (CDA) (fig. 13b), Erromenus bedardiProvancher (CDA), and E. dolichops Townes and Townes (CDA)(fig. 13c) have been examined.All the head sclerites are present with the exception of the pre-labial; the ventral part of the labial sclerite is pointed or curved so asto give the sclerite an oval to round appearance; each maxillary andlabial palp bears three sensilla in Polyblastus and two in Erromenus;the mandible is without teeth in Polyblastus but has small teeth inErromenus: the disc-shaped antenna has two sensilla; the distance ofthe closing apparatus of the spiracle from the atrium is about equalin length to the closing apparatus in Polyblastus, but the distance isabout twice the length of the closing apparatus in Erromenus: smallspines are present on the skin of both Polyblastus and Erromenus, but504675?59 3
424 PROCEEDENGS OF THE NATIONAL MUSEUM vol. no
0-1 m m
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 425
Ot mmFigure 13.?Head sclerites: a, Boethes sp. (Tryphoninae:Boethini); b, Polyblastus pedalis(Cresson) (Tryphoninae:Tryphonini); c, Erromenus dolichops Townes and Townes(Tryphoninae:Tryphonini); d, Exenterus canadensis Provancher (Tryphoninae:Cteniscini);E, Brachycyrtus prctiosus Cushman (CryptinaerBrachycyrtini), antenna not visible onpreparation. (1, antenna; 2, spiracle; 3, skin.)
426 PROCEEDINGS OF THE NATIONAL MUSEUM vol. nothe length of the skin setae is equal to three-quarters of the lengthof the mandible in Polyhlastus, whereas in Erromenus the setae aresmall and equal to one-fifth of the length of the mandible.Larval Key
1. Mandible without teeth; thi-ee sensilla on each maxillary and labial palpPolyblastusMandible with teeth; two sensilla on each maxillary and labial palp.ErromenusTribe CtenisciniFigure 13dMembers of this tribe parasitize the larvae of Argidae, Tenth-redinidae and Diprionidae. Exenterus ahrwptorius (Thunberg), E.adspersus Hartig, E. canadensis Provancher (fig. 13d), E. claripennisThomson, and E. tricolor Roman have been examined.All the head sclerites except the prelabial are present; the lateralparts of the labial sclerite meet the ventral almost at right angles;each maxillary and labial palp has two sensiUa, both round, one largeand one small; the mandible is without teeth; the antenna is disc-likeand has three prominent sensilla; the closing apparatus of the spiracleis long and slender and its distance from the atrium is roughly equalto the length of the closing apparatus; spines are conspicuous on theskin and their length is about half that of the setae.The following are figured in the literature: Exenterus ahruptorius(Thunberg) (Alorris, 1937), E. adspersus Hartig (Beirne, 1941), E.tricolor Roman (Morris, Cameron, and Jepson, 1937).Subfamily Cryptinae (=Gelinae)Figures 13e-27, 64Most members of this subfamily are ectoparasites but some are, orcan be, endoparasites. Mr. J. F. Perldns (in litt.) has informed methat in Polyiribax (Aptesini) the parasites emerge from the pupa ofthe host. Rosenberg (1934) states that he reared Cryplus sexannulatusGravenhorst and Agrothereutes batavus VoUenhoven from cocoonswithin the host pupae, but that when he reared the larvae of thesespecies they fed externally on host larvae.In this very uniform group, the head sclerites are, in general, welldeveloped, although the prelabial sclerite is absent and the epistomais very lightly sclerotized and is slender and more or less incompletedorsally, except in Gamhrus where the dorsal part is broad and com-plete; the pleurostoma is usually very lightly sclerotized; the labial
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 427
sclerite is roughly triangular in shape in most genera, but, as statedbelow, this sclerite may be circular or otherwise modified; the silkpress is well sclerotized and conspicuous and two small sensilla areoften visible just beneath the external opening of the press; eachmaxQlary and labial palp usually bears two sensilla, one round andone crescentic in shape, although three or more sensilla are presentin some genera; the labral sclerite is usually lightly sclerotized in itsdorsal part and this part may be enlarged; the mandibles are rela-tively small in most genera, except in the Aptesini where they areof moderate size; teeth may be present on the dorsal and ventralsurfaces of the blade of the mandible, on the dorsal surface only, orteeth may be absent; the antenna is usually papilliform, althoughit is disc-shaped in some Hemitelini; the closing apparatus of thespiracle may be some distance from the atrium or it may be close tothe atrium; the skin bears setae and small projections which may besufficiently sclerotized to appear as spines.Larval Key
1. Hypostoma posterior to hypostoinal spur shorter tliau hypostomal spur.BracliycyrtiniHypostoma posterior to hypostomal spur at least as long as hypostomal spur . . 22. Mandible with a long slender blade bearing a row of fine teeth along entirelength of dorsal surface SphecophaginiMandible not of this form 33. Teeth on dorsal surface of blade of mandible larger than teeth on ventralsurface '^ which are very small and few in number, except in Rhernhohius(fig. 21a) where the blade of the mandible is short, broad and well sclerotizedwith length equal to one third of that of base of mandible and width oflateral end equal to one third of width of base AptesiniIf teeth present on dorsal and ventral surfaces of blade of mandible and teethon dorsal surface markedly larger than teeth of ventral surface, then ventralteeth numerous ^^ and blade of mandible longer and more slender than inRhernhohius, with length greater than one third of that of base of mandibleand with width of lateral end less than one third of that of base 44. Closing apparatus of spiracle separated from atrium by length of trachea atleast equal to length of closing apparatus, or, if not, then epistoma notsclerotized dorsal to anterior tentorial pits HemiteliniClosing apparatus of spiracle adjoining atrium, or if not, then at least partof epistoma dorsal to anterior tentorial pits lightly sclerotized '* . . Cryptini
'2 Except Cubocephalus where the form and position of the closing apparatus of the spiracle diflerentiatesthis genus from Cryptini with a similar type of mandible and either the form of the labial sclerite or theform and position of the closing apparatus of the spiracle differentiates this genus from Hemitelini witha similar type of mandible.>' Except Trychosis, Mallochia and Lymeon (Cryptini). The following characters will distinguish thesegenera from the Aptesini: the form of the labial sclerite in Trychosis, the sharp dorsal bend of the lateral endof the stipital sclerite in Mallochia, and the heart-shaped dorsal senslllum on each labial palp in Lymeon.
'? Except Pseudischnus.
428 PROCEEDINGS OF THE NATIONAL MUSEUM vol. noTribe BrachycyrtiniFigure 13,eBrachycyrtus pretiosus Cusbman (fig. 13,e) was examined.Members of the genus Brachycyrtus are parasitic in the cocoons ofChrysopidae. The Brachycyrtini have been placed by some authorsin a tribe of the PimpHnae. From a study of the adults, Walkley(1956) reached the conclusion that the group fits best in the Cryptinae,but that additional material and knowledge might prove that itbelongs in a subfamily of its own. The larval characters support thisconclusion. The form of the mandibles and head sclerites resemblethose of the Cryptinae rather than any other group. The positionof the hypostomal spur difters from that of the Pimplinae other thanthe Labenini and Xoridini. The form of the labral sclerite differsfrom that of the Labenini. The form of the mandible differs fromthat of the Xoridini in that the blade is relatively longer. Thegroup is an isolated one on larval characters, and the short hypos-toma is distinctive. The form of the hypostoma resembles that ofthe Sphecophagini to some extent, although the hypostoma of theBrachycyrtini is considerably shorter than that of the Sphecophagini.The head of Brachycyrtus is small and delicate and the antenna wasnot clearly visible on the preparations made. It appears to bedisc-shaped. Tribe Hemitelini (^Gelini)Figures 14-19, 64Members of this tribe attack a great variety of hosts. Many areoccasionally or habitually secondary parasites. The most conspicuouscharacters of the tribe are the poorly developed epistoma and thedistance of the closing apparatus of the spiracle from the atrium.Larval Key1. Mandible without teeth 2Mandible with teeth 72. Each ventrolateral part of labial sclerite expanded 3Labial sclerite not of this shape 63. Ventral end of hypostomal spur broader than dorsal.Isdromas peruviana (Viereck)Ventral end of hypostomal spur narrower than dorsal 44. Mandibles with relatively broad blades, the tips of which do not meet inthe median line Isdromas lycaenae (Howard)Mandibles with relatively narrow blades, the tips of which meet in the medianline 55. Dorsal part of labral sclerite pointed StilpnusDorsal part of labral sclerite not pointed Atractodes
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 429
6. Labial sclerite round in shape and with lateral parts not meeting ventralapproximately at right angles ThaumatotypusLabial sclerite not round in shape and v/ith lateral parts meeting ventralapproximately at right angles Phygadeiion7. Mandible with teeth only on dorsal surface of blade 8Mandible with teeth on dorsal and ventral surfaces of blade '^ 118. Teeth few in number and relatively large BathythrixTeeth small and fine 9n. Two sensilla present on each maxillary and labial palp OtacustesSensilla not as above 1010. Three sensilla, two large and one small, present on each maxillary andlabial palp Mastms molefetae (Uchida)One large sensillum situated dorsally and two or three small sensilla situatedventrally in the form of a crescent on each maxillary and labial palp.Thysiotorus11. Labial sclerite approximately circular in shape EtheiurgusLabial sclerite not approximately circular in shape; lateral parts meet ventralapproximately at right angles 1212. Papillus of antenna reduced to disc bearing three sensilla IselixAntenna not of this shape 1313. Two sensilla present on each maxillary and labial palp 15Sensilla not as above 1414. Two sensilla of equal size together with one or two smaller sensilla present oneach maxillary and labial palp 18One large ventral sensillum and a dorsal group of smaller sensilla present oneach maxillary and labial palp Masfrus sniilhii (Packard)15. Dorsal sensillum on each maxillary and labial palp larger than ventral.EndasysDorsal sensillum on each maxillarj' and labial palp smaller than ventral orequal in size to ventral 1616. Pleurostoma more lightly sclerotized than hypostoma.Gelis tantillus (Cresson)Pleurostoma as well sclerotized as hypostoma 1717. Labral sclerite with single median expansion HeniitelesLabral sclerite not expanded in its median part and with two small dorsolateralexpansions Mastrus argeae (Viereck)18. Mandible with rounded base and relatively short blade.Gesis bruesii (Strickland)Mandible with a conical base and relatively long slender blade . . PhobetesOf the characters used in the above key, the form of the labralsclerite and its degree of sclerotization is not a good one. In some casesthe character is clear, but in others it may be obscured when the entirelength of the sclerite has not been forced into the one plane duringmounting. However, since the tribe is extremely uniform and thelabral sclerite does differ in shape and degree of sclerotization in dif-ferent genera, it was found necessary to use this character.
" Teeth on the ventral surface of the blade of the mandible are usually very small and must be looked forwith great care.
430 PROCEEDINGS OF THE NATIONAL MUSEUM
< / \
J,/v^>^?/\_/^
Figure 14.?CryptInae:Hemitelini, head sclerites: a, Bathythrix sp., antenna not visible onpreparation; b, Mastrus molestae (Uchida); c, Otacustes sp. (1, antenna, 2, spiracle;3, skin.)
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 431
3Figure IS.?CryptinaerHemltelini, head sclerites: a, Ethelurgus syrphicola (Ashmead); b,Isdromas peruviana (Viereck); c, Isdromas lycaenae (Howard). (1, antenna; 2, spiracle;3, skin.)
432 PROCEEDINGS OF THE NATIONAL MUSEUM voL.no
Figure 16.?Cryptinae:Hemitelini, head sclerites: a, Tkaumatotypus paradoxus (Zetter-stedt); B, Phohetes thyridopieryx (Riley). (1, antenna; 2, spiracle; 3, skin.)
ICHNEUMONID FINAL ESTSTAR LARVAE?SHORT 433
O-l mm
O f m m
Figure 17.?Cryptinae:Hem!telini, head sclerites: a, Gelis tantillus (Cresson); b, Hemitelesarealor (Panzer); c, Endasys subclavatus (Say). (1, antenna; 2, spiracle; 3, skin.)
434 PROCEEDINGS OF THE NATIONAL MUSEUM vol. no
;e^^^^<^'^A2 Ol mmFigure 18.?Cryptinae:Hemitelini, head sclerites: a, Thysiotorus sp.; b, Phygadeuonsubfuscus Cresson; c, Iselix sp. (1, antenna; 2, spiracle; 3, skin.)
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 435
O't m mFigure 19.?Cryptinae:Hemltelini, head sclerites: Stilpnus anthomyidiperda Viereck.(1, antenna; 2, spiracle; 3, skin.)The following have been examined: Bathythrix sp. (fig. 14a),Mastrus argeae (Viereck), M. molestae (Uchida) (fig. 14b), M. smithii(Packard), Otacustes sp. (fig. 14c), Ethelurgus syrphicola (Ashmead)(fig. 15a), Isdromas peruviana (Viereck) (fig. 15b), /. lycaenae (How-ard) (fig. 15c), Thaumatotypus paradoxus (Zetterstedt) (fig. 16a),Phobetes thyridopteryx (Riley) (fig. 16b), Gelis bruesii (Stricldand)
,
G. tantillus (Cresson) (fig. 17a), Hemiteles areator (Panzer) (fig. 17b),Endasys subclavatus (Say) (fig. 17c), Thysiotorus sp. (fig. 18a), Phy-gadeuon subfuscus Cresson (fig. 18b), Iselix sp. (fig. 18c), Stilpnusanthomyidiperda Viereck (fig. 19a), Atractodes sp. (GCV) (fig, 64a).Of these specimens, Mastrus molestae (Uchida) differs from the otherspecies of this genus examined in that the mandibular teeth are smalland are present only on the dorsal surface of the blade. M. smithii(Packard) has one large sensillum and a group of smaller sensilla on eachmaxillary and labial palp and M. argeae (Viereck) two sensilla. Inthe two species of Isdromas examined the mandible is basically similarand the ventrolateral part of each labial sclerite is expanded. Thereare, however, many differences between these species. The larvalcharacters of Gelis, Hemiteles, and Endasys indicate a close relation-ship. Members of the genus Gelis attack various small cocoons,
436 PROCEEDINGS OF THE NATIONAL MUSEUM vol. noincluding those of Ichneumonidae and Braconidae, and many para-sitize the egg cocoons of spiders.Phygadeuon, helix, StUpnus, and Atractodes resemble each other inlarval characters and all are parasites of muscoid Diptera. Dis-tinctive features of Atractodes are that the head and the base of themandibles are lightly sclerotized and the well-sclerotized blade of themandible is toothless, the several very small ridges present on thedorsal surface of the blade not being distinct enough to be called teeth.The antenna, like that of Stilpnus, is disc-shaped, but StUpnus differsfrom Atractodes not only in the key characters but also in having theblade of the mandible more slender, the ventral part of the labialsclerite more sharply narrowed in the median line, and the posteriorend of the hypostoma straight instead of slightly bent towards the dor-sal surface (compare figs. 19 and 64).The following are figured in the literatm-e: Otacustes crassuspatruelis (Cushman) (Clancy, 1946), Gelis melanoceyhala (Schrank)(Beu-ne, 1941), G. tenellus (Say) (Clancy, 1946), Hemiteles areator(Panzer) (Morris, Cameron, and Jepson, 1937), H. hemipterus (Fab-ricius) (Salt, 1931), H. simillimus (Taschenberg) (Blunk, 1952).Tribe AptesiniFigures 20-21aMost of the members of this tribe are parasites of sawflies. Char-acteristics of the larvae are the development of the lateral parts of theepistoma dorsal to the anterior tentorial pits and the relatively largemandibles. The teeth on the dorsal surface of the blade of the mandi-ble are larger than the teeth on the ventral surface in Aptesis andRhemhohius but not in Cubocephalus.Larval Key
1. Teeth on the dorsal surface of the blade of the mandible not markedly largerthan teeth on the ventral surface CubocephalusTeeth on dorsal surface of blade of mandible larger than teeth on ventralsurface 22. Blade of mandible short, broad, and well-sclerotized, with length approximatelyequal to one-third of that of base of mandible RhembobiusBlade of mandible relatively slender with length approximately equal to one-half of that of base of mandible AptesisThe following have been examined: Cubocephalus sp. (fig. 20a),Aptesis indistincta (Provancher) (fig. 20b), A. pteronorum (Graven-horst), and Rhemhohius abdominalis (Provancher) (fig. 21a).The teeth on the dorsal surface of the blade of the mandible of A.pteronorum are smaller than in A. indistincta.
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 437
-^^-^rl^^t^
Figure 20.?Cryptinae:AptesIni, head sclerites: a, Cuhocephalus sp.; b, Aptesis indtstincta(Provancher). (1, antenna; 2, spiracle; 3, skin.)
438 PROCEEDINGS OF THE NATIONAL MUSEUM vol. no
^ 6 i> /^ -^ aAO-l m mFigure 21.?Cryptinae, head sclerites: a, Rhemhohius ahdominalis (Provancher) (Aptesini);B, Sphecophaga thuringiaca Schmiedeknecht (Sphecophagini). (1, antenna; 2, spiracle;3, skin.)
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 439The following are figured in the literature: Cubocephalus abdominator(Gravenhorst) (Rosenberg, 1934), C. brumatae (Silvestri) (Silvestri,1941), Aptesis basizonia (Gravenhorst) (Morris, Cameron, and Jepson,1937). Tribe SphecophaginiFigure 21bMembers of this tribe are parasitic in the nests of Vespula andPolistes.The mandible is characteristic with its long slender blade bearing arow of fine teeth along the entire length of the dorsal surface.Sphecophaga thuringiaca Schmiedeknecht (BM) (fig. 21b) andSphecophaga sp. (CDA) were examined.Sphecophaga vesparum (Curtis) is figured by Beirne (1941) andSphecophaga sp. by Snodgrass (1935).Tribe Cryptini (=Mesostenini)Figures 22-27Members of this tribe are parasitic mostly on pupae and prepupae,or on larvae concealed in tunnels or leaf rolls. Hosts include Lepi-doptera, Symphyta, Aculeata, and spider eggs.The larvae have the lateral parts of the epistoma well developedand, in many genera, the closing apparatus of the spiracle adjoins theatrium. Larval Key1. Epistoma lightly sclerotized, broad and complete GambrusEpistoma lightly sclerotized, narrow and more or less incomplete dorsally . 22. Labial sclerite with each ventrolateral part indented TrychosisLabial sclerite not of this form 33. Closing apparatus of spiracle adjoining atrium 4Closing appratus of spiracle not adjoining atrium 104. Dorsal part of labral sclerite expanded into three lightly sclerotized lobes.CryptusDorsal part of labial sclerite not of this form 55. Six setae on prelabium 6Four setae on prelabium 76. Median-dorsal part of labral sclerite with lightly sclerotized enlargement.GoryphusMedian-dorsal part of labral sclerite without enlargement .... Mesostenus7. Dorsal part of labral sclerite divided into two lightly sclerotized bars.PolycyrtusDorsal part of labral sclerite not divided into two bars 88. Mandible with a relatively slender blade bearing a row of fine teeth on thedorsal surface and teeth on ventral surface few and small . . MallochiaMandible not of this form 9504675?59 1
440 PROCEEDINGS OF THE NATIONAL MUSEUM vol. no
Figure 22.?Cryptinae:Cryptini, head sclerites: a, Cryptus alhitarsus albitarsus (Cresson);B, Mesostenus sp. nr. gracilis Cresson; c, Polycyrtus semialbus (Cresson), antenna notvisible on preparation. (1, antenna; 2, spiracle; 3, skin.)
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 441
Figure 23.?Cryptinae:Cryptini, head sclerltes: a, Trychosis sp.; b, Gambrus canadensis(Provancher). (1, antenna; 2, spiracle; 3, skin.)
442 PROCEEDINGS OF THE NATIONAL MUSEUM vol. no
Figure 24.?Cryptinae:Cryptini, head sclerites: a, Goryphus injerus (Szepligeti); b, Hoplo-cryptus incertulus Cushman, antenna not visible on preparation. (1, antenna; 2, spiracle;3, skin.)
ICHNEIJIVIONID FINAL INSTAR LARVAE?SHORT 443
Figure 25.?Cryptinae:CryptIni, head sclerites: Nippocrypius suzukii (Matsumura)(1, antenna; 2, spiracle; 3, skin.)
9. Width of closing apparatus of spiracle approximately equal to half width ofatrium AgrothereutesWidth of closing apparatus of spiracle more than half width of atrium.Eripternimorpha10. Ventral row of teeth on mandible poorly developed LynieonVentral row of teeth on mandible well developed 1111. Epistoma not sclerotized dorsal to anterior tentorial pits . . . PseudischnusEpistoma sclerotized dorsal to anterior tentorial pits 1212. Six large setae on labrum HoplocryptusMore than six large setae on labrum 1313. Dorsal part of labral sclerite with three lightly sclerotized lobes . . EchtiirusDorsal part of labral sclerite with one lightly sclerotized lobe . NippocryptiisThe following have been examined: Cryptus alhitarsus albitarsus(Cresson) (iig. 22a), Mesostenus gracilis Cresson, Mesostenus sp. nr.gracilis Cresson (fig. 22b), Polycyrtus semialhus (Cresson) (fig. 22c),Trychosis sp. (fig. 23a), Gainbrus canadensis (Provancher) (fig. 23b), G.stokesi Cameron, Goryphus inferus (Szepligeti) (fig. 24a), Hoplocryptusincertulus Cushman (fig. 24b), Nippocrypius suzukii (Matsumura)(fig. 25a), Agrothereutes grapholithae (Uchida), Agrothereutes sp.(fig. 26a), Pseudischnus oregonensis (Cushman) (fig. 26b), Eripterni-morpha javensis Rohwer (fig. 26c), Mallochia sp. (fig. 27a), Lymeonorhum (Say) (fig. 27b), Echthrus niger Cresson (fig. 27c).
444 PROCEEDINGS OF THE NATIONAL MUSEUM vol. no
A-^-J\-</-/(-A-J^?^ /^ A A -"^0-1 mmFigure 26.?Cryptinae:Cryptini, head sclerites: a, Agrothereutes sp.; b, Pseudischnusoregonensis (Cushman); c, Eripternimorpha javensis Rohwer. (1, antenna; 2, spiracle;3, skin.)
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 445
Figure 27.?Cryptinac:Cryptini, head sclerites: a, Mallochia sp.; b, Lymeon orbum (Say);c, Echthrus niger Cresson. (1, antenna; 2, spiracle; 3, skin.)
446 PROCEEDINGS OF THE NATIONAL MUSEUM vol. noAgrothereutes grapholithae (Uchida) differs from the species illus-trated (fig. 26a) in that there is but one median expansion of thelabral sclerite and there are eight large setae on the labrum insteadof six.The following are figured in the literature : Cryptus inornatus Pratt(Simmonds, 1948), C. laborator laborator (Thunberb) (Beirne, 1941),C. sexannulatus Gravenhorst (Rosenberg, 1934), Agrothereutes abhrevi-ator (Fabricius) (Morris, Cameron, and Jepson, 1937), A. batavusVollenhovon (Rosenberg, 1934), Ischnus polytomi (Tschek) (Morris,Cameron, and Jepson, 1937), Echthrus reluctator (Linnaeus) (Bau-mann, 1933).Subfamily Ickneumoninae (= Joppinae, =Phaeogeninae)Figures 28-37This is a very distinct and uniform subfamily whose members areinternal parasites of the Lepidoptera. They oviposit in the host larvaor pupa but always emerge from the pupa.The epistoma is lightly to heavily sclerotized and the pleurostomaand hypostoma are always well sclerotized; sclerotized areas may bepresent lateral and dorsal to the pleurostoma and epistoma and, to amore limited extent, the hypostoma; sensilla are frequently presenton the epistoma and pleurostoma; the hypostomal spur and stipitalsclerite are absent; the labial sclerite is usually absent but may some-times be seen as a very lightly sclerotized strip at the edge of the pre-labial area ; each maxillary and labial palp is in the form of a flatteneddisc bearing several sensilla, usually about five to each palp; the silkpress is lightly sclerotized and two small sensilla are present ventralto the press; the prelabial sclerite is absent; groups of setae and sensillaare situated on the clypeolabral area, often on lightly sclerotizedplates the shape of which is often characteristic of a genus ; the mandi-bles are large and well sclerotized and do not have teeth on the blade;the antenna is disc-shaped; the spiracle has an oval atrium, and thelarge, thiclc-walled closing apparatus adjoins the atrium; the skin issmooth with small setae and no spines.Larval Key
1. Hypostoma sharply bent TroginiHypostoma may be curved but never sharply bent 22. Mandible broad and length of blade is equal to or less than one-third lengthof mandible ListrodrominiMandible less broad and length of blade is more than one-third length ofmandible 3
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 447
01 m mFigure 28.?Ichneumoninae:Phaeogenini, head sclerites: a, Phaeogenes hariolus (Creseon);B, Rhexidermus huardi (Provancher). (Antenna not visible on preparation; 2, spiracle;3, skin.)
448 PROCEEDINGS OF THE NATIONAL MUSEUM vol. uo
3. A lightly sclerotized plate is present on the clypeus ventral to and continuouswith the epistoma and dorsal to the anterior pleurostomal processes; inPhaeogenes and in Diadromus (Given, 1944) the ventrolateral edges of theplate are prominent as sclerotized bars PhaeogeniniA lightly sclerotized plate of this shape is not present on the clypeus .... 44. Clypeolabral region with two slender and lightly sclerotized bands curvingdorsaUy and with a line of setae which follows the curve situated beneatheach band PlatylabiniClypeolabral region without sclerotized bands of this shape and position i" . 55. The sclerotized area lateral to each pleurostoma is almost as well sclerotizedas the pleurostoma so that the lateral limit of the sclerite is not clearlydefined EurylabiniIf sclerotized area present lateral to each pleurostoma, then pleurostomamore heavily sclerotized than this area and with lateral limit clearlydefined '' 66. Setae and seusilla on clypeolabral region arranged in two elongate-oval areaswith a circular area containing two sensilla beneath each oval area.ProticlmeumoniniSetae and sensilla of clypeolabral region not as above .... IchneumoniniThe differences between most tribes are slight in this uniformsubfamily. During mounting the lightly sclerotized parts of thecranium adjoining the epistoma are jQattened into various shapes.The figures show this region as it appears in the preparations, butit is unlikely that these shapes have any taxonomic significance.Tribe Phaeogenini (= Aloniyini)Figure 28Larval Key
1. With a sclerotized bar extending across each ventrolateral edge of the lightlysclerotized plate on the clypeus PhaogenesDiadromus *^No sclerotized bar present along each ventrolateral edge of the lightly sclero-tized plate on the clypeus RhexidermusThe following were examined: Phaeogenes ater (Cresson), P.haeussleri Uchida, P. hariolus (Cresson) (fig. 28a) , P. hebrus (Cresson)
,
P. vincibilis (Cresson), P. walshiae walshiae Ashmead, Rhexidermushuardi (Provancher) (fig. 28b).The following are figured in the literature: Phaeogenes nigridensWesmael (Goidanich, 1931), Diadromus collaris (Gravenhorst) (Given,1944), Proscus suspicax (Wesmael) (Beirne, 1941), Herpestomusbrunnicornis (Gravenhorst) (Beirne, 1943).
" Except Pseudamblyteles (Ichneumonini) , where there is no line of setae beneath each sclerotized bandas in the Platylabini.1' Except Melanichneumon (Ichneumonini), where the numerous setae on the prelabium distinguishthis genus from Probolus.18 Of Given (1944).
ICHNEUMONID FINAL INSTAR LARVAE SHORT 449Tribe PlatylabiniFigure 29Platylabus darus (Cresson) was examined.The pair of lightly sclerotized plates situated on the clypeolabralregion above the setae and sensilla distinguish this ichneumoninefrom all others examined except Pseudamhlyteles. In Pseudamblytelesthere is no line of setae beneath and following the curve of eachsclerotized plate as in Platylabus.Tribe ListrodrominiFigure 30Members of this tribe prefer Lycaenidae as hosts.The broad mandibles with their very short blades are distinctive.Larval KeyL Each maxillary and labial palp with three sensilla, the middle one raised as aprojection AnisobasEach maxillary and labial palp with five sensilla, but none raised as a pro-jection Listrodromus
Figure 29.?Ichneumoninae:Platylabini, head sclerites: Platylabus clarus (Cresson)(Antenna not visible on preparation; 2, spiracle; 3, skin.)
450 PROCEEDINGS OF THE NATIONAL MUSEUM vol. no
Figure 30.?Ichneumoninae:Listrodromini, head sclerites: a, Anisobas sp. (antenna notvisible on preparation; 2, spiracle; 3, skin); b, Listrodromus nycthemerus (Gravenhorst)(other structures not visible on preparation).
ICHNEUMONID FINAL INSTAR LARVAE^?SHORT 451The following were examined: Anisobas sp. (CDA) (fig. 30a),Listrodromus nycthemerus (Gravenhorst) (BM) (fig. 30b).Tribe EurylabiniFigure 31Probolus sp. (CDA) was examined.The absence of a sharp line of demarcation between each pleuro-stoma and the sclerotized area lateral to it distinguish this ichneu-monine from all others examined except Melanichneumon, which isdistinguished by the numerous setae on the prelabial region.
A ^
I 1O- 1 mmFigure 31.?Ichneumoninae-.Eurylabini, head sclerites: Probolus sp. (antenna not visibleon preparation; 2, spiracle; 3, skin.)Tribe IchneumoniniFigures 32-35In the following key reference is made to setae and sensilla, butthere is no distinction between a small seta and a sensQlum.Larval Key1. Epistoma broad and lightly sclerotized CarinodesEpistoma narrow and well sclerotized 22. Some eighteen setae present on prelabium MelanichneumonNo more than six setae present on prelabium 3
452 PROCEEDENGS OF THE NATIONAL MUSEUM
Figure 32.?Ichneumoninae-.Ichneumonini, head sclerites: a, Melanichneumon hrevicinctor(Say); b, Cratichneumon unifasciatorius (Say). (Antenna not visible on preparation;2, spiracle; 3, skin.)
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 453
Figure 33.?Ichneumoninaerlchneumonini, head sclerites: a, Aophcs velox (Cresson)antenna not visible on preparation; b, Chasmias scelestus (Cresson). (1, antenna; 2,spiracle; 3, skin.)
454 PROCEEDINGS OF THE NATIONAL MUSEUM vol.
Figure 34.?Ichneumoninae:Ichneumonini, head sclerites: a, Pseudamhlyteles nuncius(Cresson); b, Amblyteles inconstans (Cresson). (Antenna not visible on preparation;2, spiracle; 3, skin.)
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 455
Figure 35.?IchneumonInae:Ichneumonini, head sclerites: a, Ichneumon amhulatoriusFabricius; b, Carinodes havenensis (Cameron). (1, antenna; 2, spiracle; 3, skin.)504675?59 5
456 PROCEEDINGS OF THE NATIONAL MUSEUM vol. no
3. Clypeolabral region with ten setae arranged in a line and two groups each oftwo sensilla beneath this line CratichneumonSetae and sensilla arranged in two groups on clypeolabrum and not in aline 44. Clypeolabral setae grouped as shown (fig. 35a) on two lightly sclerotized platesshaped as shown (fig. 35a) IchneumonSetae and sensilla not grouped as shown (fig. 35a) on plates shaped as shown(fig. 35a) 55. Raised areas on clypeolabrum containing sensilla narrow and straight . AoplusRaised areas on clypeolabrum containing setae or sensilla more broad andnot straight 66. Each raised area containing sensilla on clypeolabrum curved dorsally.AmblytelesEach raised area containing setae or sensilla on clypeolabrum not curveddorsally 77. Each raised area on clypeolabrum with a lightly sclerotized dorsal bar andcontaining six sensilla PseudamblytelesEach raised area on clypeolabrum without sclerotized dorsal bar and con-taining seven setae ChasmiasThe following have been examined: Melanichneumon hrevicinctor(Say) (fig. 32a), M. ruhicundus (Cresson), Cratichneumon duplicatus(Say), C. unifasciatorius (Say) (fig. 32b), Aoplus velox (Cresson)(fig. 33a), Chasmias scelestus (Cresson) (fig. 33b), Pseudamblytelesanimosus rubellus (Cresson), P. nuncius (Cresson) (fig. 34a), P.subfuscus (Cresson), Amblyteles inconstans (Cresson) (fig. 34b), A.subrufus (Cresson), Ichneumon ambulatorius Fabricius (fig. 35a), /.laetus Brulle, /. rujiventrus incertus Cresson, and Carinodes havanensis(Cameron) (fig. 35b).The following are figmi-ed in the literature: Melanichneumon rubi-cundus (Cresson) (Wishart, 1949), Aoplus pictus (Gravenhorst)(Beu-ne, 1941), Amblyteles armatorius (Foerster) (Beirne, 1941),Ichneumon suspiciosus Wesmael (Cameron, 1950, 1951).Tribe ProtickneumoniniFigure 36aCoelichneumon pepticus (Cresson) (fig. 36a) and Protichneumon sp.(GCV) were examined.There are no clear characters differentiating this tribe from theIchneumonini. The head parts are heavily sclerotized and there is alarge sclerotized area of the cranium lateral to each pleurostoma. InCoelichneumon the ocular line (shown by the antenna in fig. 36a) iswell sclerotized and conspicuous. It is also conspicuous in Protich-neumon. The specimen of Protichneumon was not figured since thelabral setae and sensilla were not clearly visible on the preparation;however, their arrangement appeared to be similar to those of Coelich-neumon.
ICHNEUMONID FINAL INSTAR LARVAE^?SHORT 457
O -1 narnFigure 36.?Ichneumoninae, head sclerites: a, Coelichneumon pepticus (Cresson) (Protich-neumonini); b, Tragus pennator (Fabricius) (Trogini), antenna not visible on preparation.(1, antenna and ocular line; 2, spiracle; 3, skin.)
458 PROCEEDINGS OF THE NATIONAL MUSEUMLarval Key
1. Three prominent setae situated beneath each labial palp.. . CoelichneumonSix prominent setae situated beneath each labial palp. . . . ProtichneumonTribe TroginiFigure 36bSpecies of Tragus and Macrojoppa are parasites of Papilionidae.The rest of the genera attack Sphingidae.Tragus pennator (Fabricius) (fig. 36b) was examined. This speciesdiffers from other Ichneumonines examined in that the hypostoma issharply bent. Subfamily MesochorinaeFigure 37All members of this subfamily are believed to be endoparasites andsecondary parasties.Mesochorus discitergus (Say) (fig. 37) and Mesochorus sp. wereexamined.The larval characters of the specimens examined indicate anisolated group. Those head sclerites present are lightly sclerotized;the epistoma is unsclerotized; the pleurostoma is present; only themedian part of the hypostoma is sclerotized in Mesochorus, but theentire hypostoma is sclerotized in Astiphromma strenuum (Holmgren)
0-1 mFigure 37.?Mesochorinae, head sclerites: Mesochorus discitergus (Say). (Antenna notvisible on preparation; 2, spiracle; 3, skin.)
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 459(Beii-ne, 1941); the hypostomal spur is very lightly sclerotized; thestipital sclerite is slender and its lateral end has a small enlargementbearing a sensillum; the labial sclerite is slender; the silk press is notsclerotized; each maxillary and labial palp bears two sensLlla,one largeand one small; there is no prelabial sclerite and no labral sclerite;two small sensilla are present on the labrum, but labral, maxillary,and prelabial setae appear to be absent; the form of the mandible isdistinctive, the base having only the circumference sclerotized andwith the blade long, slender, and slightly curved; the width of thebase of the mandible is approximately equal to two-thirds the length ofthe blade ; the spiracle is relatively small and the length of the thin-walledclosing apparatus, which adjoins the atrium, is approximately equalto twice the depth of the atrium; the skin bears small projections butsetae could not be seen. Larval Key
1. Hypostoma with only median part sclerotized MesochorusHypostoma with entire length sclerotized Astiphromma i*The following are figured in the literature : Mesochorus fulguransCurtis (Beirne, 1941), M. vitticollis Holmgren (Beirne, 1943).The A4esochorinae follow the Anomalinae in the classification byWalldey (1958). The larval characters of the Mesochorinae are verydifferent from those of the Anomalinae and in the present study theMesochorinae have been placed near the Lissonotinae. The roundedlabial sclerite of the Mesochorinae resembles that of the Lissonotinae.The mandible, however, is distinctive in form and differs from thatof all other Ichneumonids. On larval characters the Mesochorinaeare best regarded as an isolated group.Subfamily LissonotinaeFigures 38-40Members of this subfamily are internal parasites of caterpillars.The characters show relationships to those of the Ophioninae andMesoleiinae. The epistoma is not sclerotized dorsally except inExetastes; the pleurostoma is lightly sclerotized to well sclerotized;the hypostoma is long in the Glyptini and Banchini, but in theLissonotini it is short and does not extend laterally beyond the lateralend of the stipital sclerite; the hypostomal spur and stipital scleriteare well developed; the labial sclerite, which is relatively large, isbasically round to oval and the ventral part is often lightly sclerotizedor unsclerotized; the silk press is large; a prelabial sclerite is usuallypresent and two sensilla are situated on this sclerite; each maxillaryI'OfBeime (1941).
460 PROCEEDINGS OP THE NATIONAL MUSEUM vol. noand labial palp contains one large sensillum and one to three smallersensilla; the labral sclerite is absent; the mandibles are relatively smalland consist of a large base and a small slender blade; this blade maybe toothless or may have small blunt teeth on its dorsal and ventralsurfaces; in some genera a lightly sclerotized band is present connect-ing the posterior pleurostomal processes across the dorsal surface ofthe food meatus; the antenna is disc-shaped; the closing apparatusof the spiracle adjoins the atrium except in Glypta; the skin has smallsetae and small conical projections but no spines.Larval Key
1. Hypostoma short and not extending laterally beyond lateral end of stipitalsclerite LissonotiniHypostoma long and extending laterally beyond end of stipital sclerite . . 22. Epistoma complete, or, if not, then with more than 10 setae present on pre-labium BanchiniEpistoma incomplete; less than 10 setae on prelabiiim GTyptiniTribe GlyptiniFigure 38aGlypta sp. was examined.With its rounded labial sclerite which is incomplete ventrally andits lightly sclerotized prelabial sclerite, Glypta resembles the Lis-sonotini. The long hypostoma resembles that of the Banchini. As insome Banchini and some Lissonotini a sclerotized bar connecting theposterior pleurostomal processes is present. The mandibles aredistinctive with their slender toothless blades and, unlike otherLissonotinae, the closing apparatus of the spiracle does not adjointhe atrium.Glypta jumiferanae (Viereck) is figured by Brown (1947), G.haesitator Gravenhorst by Cameron (1938), and G. parvicaudataBridgman by Beu-ne (1941).Tribe LissonotiniFigures 38b, c, 39Members of this tribe are parasites of caterpillars in burrows andleaf rolls. Larval Key
1. Labial sclerite with ventral part unsclerotized or not as well sclerotized aslateral parts 2Labial sclerite with ventral part as well sclerotized as lateral part .... 42. Mandible without teeth LissonotaMandible with teeth 3
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 461
0-1 mmFigure 38?Lissonothiae, head sclerltes: a, Glypta, sp. (Glyptini); b, Lamfronota sp. nr,sesiovora (Rohwer) (Lissonotini); c, Leptobatofsis sp. nr. lepidus (Cameron) (LIssonotini).(Antenna not visible on preparation; 2, spiracle; 3, skin.)
462 PROCEEDINGS OF THE NATIONAL MUSEUM
O ? 1 rn mFigure 39.?Lissonotinae:Lissonotini, head sclerites: a, Lissonota'brunnea (Cresson);B, Pimplopterus rubricus (Cresson); c, Asphragis mirabilis (Cresson). (Antenna notvisible on preparation; 2, spiracle; 3, skin.)
ICHNEUMONID FINAL INSTAR LARVAE^?SHORT 463
3. Dorsal ends of labial sclerite broad AsphragisDorsal ends of labial sclerite narrow Leptobatopsis4. Hypostoma not extending laterally beyond hypostomal spur . LampronotaHypostoma with short lateral bar beyond hypostomal spur . PimplopterusThe species of Lampronota figured is peculiar in that there is alightly sclerotized band running along the ventral edge of the labrum.This band is distinct from the band connecting the posterior pleuro-stomal processes across the dorsal surface of the food meatus in somegenera. The functions of these bands are not obvious. Beirne (1941)does not figure a labral band in L. catenator (Panzer) although he doesfigm^e a band between the posterior pleurostomal processes.The following were examined : Lampronota sp. nr. sesiovora (Rohwer)(fig. 38b), Leptobatopsis sp. nr. lepidus (Cameron) (fig. 38c), Lissonotabrunnea (Cresson) (fig. 39a), Pimplopterus rubricus (Cresson) (fig.39b), Asphragis mirabilis (Cresson) (fig. 39c).Lampronota catenator (Panzer) and Syzeuctus maculatorius (Fab-ricius) are figured by Beirne (1941). S. maculatorius is similar toAsphragis although teeth do not appear to be present on the mandible.Tribe BanchiniFigure 40Larval Key
1. Epistoma present ExetastesEpistoma absent 22. Ventral part of prelabial sclerite more lightly sclerotized than dorsal parts.CeratogastraVentral part of prelabial sclerite as well sclerotized as laterial parts . BanchusBanchus and Ceratogastra are very similar. The T-shaped prelabialsclerite resembles that of many Ophioninae. Exetastes differs fromother Lissonotinae in having a complete epistoma, but the remainingcharacters, such as the shape of the mandible, are typical of the sub-family. Apart from the epistoma, Exetastes differs from the other twogenera of the Banchini examined in that there are teeth on the man-dibles. However, the structure of the spiracle is basically similar inthe three genera, the closing apparatus being as long as two or threetimes the depth of the atrium. In the Lissonotini the closing apparatusis approximately of the same length as the atrium.The following were examined: Exetastes bijenestratus Cushman(fig. 40a), E. illinoiensis (Walsh), Ceratogastra ornata ornata (Say)(fig. 40b), Banchusfemoralis Thomson (fig. 40c), B.fiavescens Cresson.The following are figured in the literature: Exetastes cinctipes(Ratzeburg) (Beirne, 1941), Exetastes sp. (Snodgrass, 1935), Banchusfemoralis Thomson (Beirne, 1941).
464 PROCEEDINGS OF THE NATIONAL MUSEUM
O-t mmFigure 40.?Lissonotinae:Banchini, head sclerites: a, Exetastes hifen estratus Cushman;B, Ceratogastra ornata ornata (Say); c, Banchus femoralis Thomson. (1, antenna; 2,spiracle; 3, skin.)
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 465Subfamily MesoleiinaeFigures 41-44Members of this subfamily are internal parasites of Tenthredi-noidea.^"The dorsal part of the epistoma is unsclerotized or lightly sclero-tized; the pleurostoma is usually lightly sclerotized: the hypostomaand hypostomal spur are well sclerotized, the hypostomal spur beingrelatively longer than in most Ophioninae; the stipital sclerite is welldeveloped and a lightly sclerotized cardo is sometimes present; thelabial sclerite is present and may be incomplete ventrally; in somegenera the dorsal ends of the labial sclerite bear small bubble-likeprojections; a prelabial sclerite is present and two sensilla are usuallypresent on the dorsal part of this sclerite; the maxillary and labialpalps are relatively large and each bears two to three sensilla ; the silkpress is conspicuous; the labral sclerite is absent, except in Opheltesand Protarchus; there are two main types of mandible, one having arounded and lightly sclerotized base with a relatively straight bladewhich may be short, the other having a rather square base and acurved blade; the antenna is disc-shaped; with the exception of Eucerosand Opheltes where the closing apparatus of the spiracle is small, thespiracle has a thin-walled closing apparatus with a length which istwo to three times the depth of the atrium; the skin bears very smallsetae and small projections which in Lophyroplectus are sufficientlysclerotized to be described as spines.The Mesoleiinae have many features resembling the Ophioninae.In the key to the subfamilies it was found necessary to separate theOphioninae into tribes in order to key out the Mesoleiinae from thissubfamily. The larval characters of the Mesoleiinae do, however,indicate a fairly distinct group. The type of mandible of Rhorus,with its rounded base and very small blade, is distinctive. Themandible of Hypsantyx is basically similar although the blade isrelatively larger. The mandible of Hypsantyx, in turn, resembles thatof other Mesoleiini and that of the Euryproctini. The mandible ofScolobates and Euceros is similar to that of most of the Ophioninaein that there is a rather square base and a curved blade. But the shapeof the labial sclerite of Scolobates connects this genus to the remainingMesoleiinae. The labial sclerite of Euceros, with its plate-like expan-sion of the ventral part, resembles that of some genera in the Ophio-ninae, Campoplegini. In Opheltes (Mesoleiinae, Mesoleiini), however,there is a smaller plate-like expansion of the ventral part of the labialsclerite and this may connect to the condition in Euceros. The spu*acleof Euceros, with its relatively small closing apparatus, resembles that
2? Euceros frigidus Cresson has been recorded as an lntemalj)araslto o( Lepldoptera.
466 PROCEEDINGS OF THE NATIONAL MUSEUM vol. no
of the Ophioninae, Campoplegini, and, ?with the exception of Opheltes,differs from that of the remaining Mesoleiinae.It has not been found possible to separate the ^Mesoleihii and Eury-proctini on larval characters. Lamachus and Hypsantyx with theirincomplete labial sclerites, the dorsal ends of which hare bubble-likeprojections, resemble the Eurvproctini rather than Opheltes, Mesoleiusand Lopkyroplectus.Townes and Townes (1951) place Opheltes in a subtribe Perilissinaand Mesoleius and Lamachus in a subtribe Mesoleiina of the Mesoleiini.The larval characters do not appear to support this grouping.Larval Key1. Mandible ^-ith rounded and very lightly sclerotized base and very smallsclerotized blade of length less than radius of base PioniniMandible not of this form 22. Labial sclerite with ventral part expanded into plate constituting almost halflength of sclerite EuceratiniLabial sclerite not of this form 33. A hghtly sclerotized plate is present across labrum, and the labral setae aresituated on this plate ScolobatiniA Ughtly sclerotized plate not present on labrum 44. Labial sclerite vrith ventral part well sclerotized or, if not, then as wellsclerotized as lateral parts.Opheltes, Mesoleius, and Lopkyroplectus of MesoleiiniLabial sclerite with ventral part unsclerotized or not as well sclerotized aslateral parts. Eiiryproctini, and Lamachus and Hypsantyx of MesoleiiniTribe ScolobatiniFigure 41aMembers of this tribe are parasitic on argid sawflies.Scolobates auricnlatiLS (Fabricus) (CDA) was examined. Themandibles of this species resemble those of the Ophioninae,Campoplegini, but the remaining characters are similar to those ofmany Mesoleiinae.Distinctive structures are the hghtly sclerotized bar across thelabrum and a lightly sclerotized plate which appears to be present onthe dorsal surface of the food meatus. This may be the suspensoriumof the hypophar\Tix (see Short, 1952, figs. 6-8) but, as seen in a castskin, it appears to be present on the dorsal surface of the food meatusand therefore distinct from the suspensorium. Living materialcould not be obtained for sections to decide this point.
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 467
. 1O-t m m
O ? t rrs mFigure 41.?Mesoleiinae, head sclerites: a, Scolohates auriculatus: (Fzhndus) (Scolobatini);B, Euceros thoracicus Cresson (Euceratini); c, Rhorus clapini (Provancher) (Pioninl)jantenna not visible on preparation. (1, antenna; 2, spiracle; 3, skin.)
468 PROCEEDINGS OF THE NATIONAL MUSEUIVI vol. noTribe EuceratiniFigure 41bSpecies of Euceros have been recorded mainly from Tenthredinoidea,but E. jridigus Cresson has been recorded from Lepidoptera.Euceros thoracicus Cresson was examined. This species shows astrong resemblance to many Ophioninae, Campoplegini, but themandibles also resemble those of the Scolobatini and the expansionof the ventral part of the labial sclerite is also seen, although to alesser extent, in Opheltes. The small closing apparatus of the spiracleis also seen in Opheltes. Tribe PioniniFigure 41cRhorus clapini (Provancher) was examined.This is a somewhat isolated form, but the labial sclerite, althoughvery slender, does resemble that of most Mesoleiinae in being in-complete ventrally. The type of mandible is also found, in a modifiedform, in the Euryproctini and Mesoleiini.Rhorus mesoanthus (Gravenhorst) is figured by Beirne (1941).Tribe MesoleiiniFigures 42, 43Larval Key
1. With labial sclerite complete ventrally 2With labial sclerite very lightly sclerotized or unsclerotized ventrally .... 42. Labral sclerite present *' OpheltesProtarchiis 22Labral sclerite absent 33. Six setae on prelabium MesoleiusFour setae on prelabium Lophyroplectus4. Posterior end of hypostoma with small expansion HypsantyxPosterior end of hypostoma without small expansion LatnachusThe broad ventral end of the hypostomal spm- figured in Lamachusvirginianus (Rohwer) appears to be present only in this species.In other species of Lamachus the ventral end of the hypostomal spuris slender. In most species of Lamachus examined the dorsal ends ofthe labial sclerite had pronounced bubble-shaped projections similarto those of Hypsantyx and the Euryproctini.The following have been examined: Opheltes glaucopterus jlavi-pennis (Provancher) (fig. 42a), Mesoleius tarsilas (Cresson), M.tenthredinis Morley (fig. 42b), Lamachus albopictus Cushman, L.
" Opheltes differs from Profarchus in that the ventral part of the labial sclerite is less pointed.M Of Beirne (1941).
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 469
O ? 1 TnmFigure 42.?Mesoleiinae:Mesoleiini, head sclerltes: a, Opheltes glaucoptenis flavipennis(Provancher) ; b, Mesoleius tenthredinis Morley, antenna not visible on preparation.(1, antenna; 2, spiracle; 3, skin.)
470 PROCEEDINGS OF THE NATIONAL MUSEUM
Ol mmFigure 43.?Mesoleiinae-.Mesoleiini, head sclerites: A, Latnachus virginianus (Rohwer),B, Hypsantyx lituratorius (Linnaeus); c, Lophyropkctus nipponensis Cushman. (1antenna; 2, spiracle; 3, skin.)
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 471
contortionis Davis, L. eques (Hartig), L. lophyri (Ashmead), L.ruficoxalis (Cushman), L. tsugae Cushman, L. virginianus (Rohwer)(fig. 43a), Hypsantyx lituratorius (Linnaeus) (fig. 43b), Lophyroplectusnipponensis Cushman (fig. 43c).The following are figured in the literature: Mesoleius tenthredinisMorley (Beirne, 1941), Protarchus testatorius (Thunberg) (Beirne,1941), Lamachus sp. (Morris, Cameron, and Jepson, 1937), Hypsantyxlituratorius (Linnaeus) (Beirne, 1941), Lophyroplectus luteator (Thun-berg) (Beirne, 1941). Beirne (1941, pp. 151, 153) figures lateralprojections on the labial sclerite in the region of the stipital scleritein Mesoleius and Lophyroplectus. These structures were not seen.It is probable that lobes on the median end of each stipital scleritewere mistaken for lobes on the labial sclerite.Tribe EuryproctiniFigure 44Larval Key1. Ventral part of prelabial sclerite absent SyoomelixVentral part of prelabial sclerite lightly sclerotized 22. Three sensilla on each labial palp IpoctoninusTwo sensilla on each labial palp PolytenisThese three genera are very similar.The following were examined: Synomelix sp. (fig. 44a), Polyterusolympiae (Ashmead) (fig. 44b), Ipoctoninus striatus (Davis) (fig. 44c).Subfamily CollyriiiiaeFigure 45aCollyria calcitrator (Gravenhorst) w^as examined. This is a veryisolated species with the larval characters showing no relationshipto those of any other ichneumonid. It is endoparasitic in the sawflyCephus.The lateral parts of the epistoma are very lightly sclerotized andbroad, forming plates on the lateral parts of the clypeus ; each pleuro-stoma is lightly sclerotized and bears about five sensilla; there are noother head sclerites : the maxillary and labial palps are represented bysmall sensilla; there is no sclerotized silk press; about 12 sensilla arepresent on the labrum; the mandibles are unsclerotized and arewithout teeth; they can be detected in specimens cleared in Faure'sfluid, but must be stained in order to be seen clearly; the antenna isdisc-shaped; the spiracle has a long, thin-walled closing apparatuswith a length which is five to sLx times the depth of the atrium; theskin is very smooth with small projections and small setae.
504675?59 6
472 PROCEEDENGS OF THE NATIONAL MUSEUM vol. no
O ? 1 mmFigure 44.?MesoleiinaeiEuryproctini, head sclerites: a, Synomelix sp.; b, Polyterusolympiae (Ashmead); c, Ipoctoninus striatus (Davis). (1, antenna; 2, spiracle; 3, skin.)
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 473
Ot m m
Olmm
Figure 45.?Head sclerites: a, Collyria calcitratorJGravenhoTSt) (CoUyriinae); b, Orthopelmamediator (Thunberg) (Orthopelmatinae). (1, antenna; 2, spiracle; 3, skin.)
474 PROCEEDINGS OF THE NATIONAL MUSEUM vol. noC. calcitrator is figured by Salt (1931) and a large sclerotized plateis shown underlying the labial area. This plate is the suspensoriumof the hypopharynx (see Short, 1952), and is figured here, althoughin a different position (fig. 45a). The suspensorium is an internalskeletal structui'e forming part of the ventral wall of the cibarial partof the stomodaeum, and the position in which it is seen depends onthe position into which it is forced during mounting.Subfamily OrthopelmatinaeFigure 45bOrthopelma mediator (Thunberg) was examined. The members ofthis genus are endoparasitic in the cyuipoids Diasirophus on Ruhusand Diplolepis on Rosa.The larval characters resemble those of the Ichneumoninae, althoughthe form of the mandible is different, the hypostoma is more lightlysclerotized, and disc-shaped labial palps are absent.The epistoma and pleurostoma are moderately sclerotized and verylightly sclerotized areas are present dorsal to the epistoma and dorso-lateral to the plem'ostoma; the hypostoma is very lightly sclerotized;the lateral parts of the labial sclerite are very faintly sclerotized andfolds along the median part of the ventral edge of each maxilla mayappear as faintly sclerotized bands; the remaining head sclerites areabsent; the maxillary palps are represented by flat discs but thelabial palps are represented bj" setae; a lightly sclerotized silk press isvisible; the mandible is relatively large and well sclerotized and hasa curved blade containing a deep groove on the inner wall of which issituated a prominent tooth; the anterior tentorial pits are prominent;the antenna is disc-shaped; the spiracle is relatively very small withan oval atrium and the closing apparatus, which adjoins the atrium,is equal in length to twice the depth of the atrium; the skin is smoothwith small setae and no projections.Orthopelma mediator as figured by Beu'ne (1941) shows a toothlessmandible, disc-shaped labial palps, and a well-sclerotized hypostoma.These structures have not been seen in any specimen of 0. mediatorexamined in the present study.Subfamily PlectiscinaeFigure 46This is a very isolated subfamily and little is known about itsbiology. The usual hosts are believed to be Fungivoridae. Thelarval characters suggest that the group is endoparasitic.Megastylus sp. (fig. 46a) and Plectiscus varius (Haliday) (GCV)(fig. 46b) were examined.
ICHNEUMONID FIXAL INSTAR LARVAE?SHORT 475
I 1 oO ? 1m mFigure 46.?Plectiscinae, head sclerites: a, Megastylus sp., antenna not visible onpreparation; b, Plectiscus varius (Haliday). (1, antenna; 2, spiracle; 3, skin.)
476 PROCEEDINGS OF THE NATIONAL MUSEUM vol. noThe epistoma is unsclerotized ; the pleurostoma is lightly sclerotized
;
the hypostoma is short and lightly or very lightly sclerotized; thehypostomal spur and stipital sclerite are fused, the stipital scleritenot extending laterally beyond its point of meeting with the hypo-stomal spur; the labial sclerite is somewhat square in shape and theventral part is relatively broad; each maxillary and labial palp islarge and each bears two sensilla, one of which is relatively large;the silk press is lightly sclerotized; the labral sclerite is absent; themandibles are relatively small and are triangular in shape; they arevery lightly sclerotized and are without teeth; the antenna is disc-shaped ; in Alegastylus the closing apparatus of the spuacle is slightlysmaller than the atrium and adjoins the atrium; in Plectiscus theclosing apparatus of the spiracle is longer than the depth of theatrium and is separated from the atrium by a length of trachea equalto the length of the closing apparatus ; the skin bears small spines andsmall projections. Larval Key1. Hypostomal spur and stipital sclerite as well sclerotized as labial sclerite.MegastylusHypostomal spur and stipital sclerite not as well sclerotized as labial sclerite.PlectiscusSubfamily DiplazoninaeFigure 47Members of this subfamily are endoparasitic in Syi'phidae. Theyoviposit into the egg or young larva of the host and emerge from thepuparium. The subfamily is an isolated group.The following were examined: Diplazon laetatorius (Fabricius)(fig. 47a), D. orhitalis (Cresson), D. scutellaris (Cresson), Zootrephusrufiventrus (Gravenhorst) (fig. 47b) (the head parts other than thelabium were damaged in this specimen), Syrphoctonus agilis (Cresson),and aS. maculifrons (Cresson) (fig. 47c).The epistoma is unsclerotized; the pleurostoma is lightly sclerotized;a small part of the hypostoma is very lightly sclerotized as is a smallpart of the hypostomal spur; the stipital sclerite is absent; the labialsclerite is well sclerotized and of characteristic shape with a ventralspine-like projection; the maxillary and labial palps are present, butsetae appear to be absent from the maxillae and labium; there isa faintly sclerotized area at the dorsal end of the labial sclerite whichmay represent the silk press; the labral sclerite is absent; groups ofsensilla are present on raised areas of the labrum; the mandibles areusually very lightly sclerotized although the blade is lightly sclerotizedin some species; the antenna was not seen in any cast skin and is
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 477
O -1 mm
O ? 1 m m
,-1 ;;i
Figure 47.?Diplazoninae, head sclerites: a, Diplazon laetatorius (Fabricius); b, Zootrephusrufiventrus (Gravenhorst); c, Syrphoclonus maculifrons (Cresson). (Antenna not visibleon preparation; 2, spiracle; 3, skin.)
478 PROCEEDINGS OF THE NATIONAL MUSEUM vol. nopresumably disc-shaped with an unsclerotized circumference; thespiracle has an oval atrium and the closing apparatus, which has thinwalls, adjoins the atrium in some genera but not in others; the closingapparatus has a length equal to five to seven times the depth ofthe atrium; the skin is very smooth and appears to lack setae andprojections. Larval Key
1. Lateral parts of labial sclerite produced into relatively sharp angles and notrounded SyrphoctomisLateral parts of labial sclerite less sharp and more rounded 22. Labial palps lobed Promethus ^Labial palps oval 33. Length of labial spine approximately equal to depth of main ventral part oflabial sclerite BiplazonLength of labial spine shorter than depth of main ventral part of labial sclerite.ZootrephusThe following are figured in the literature: Diplazon Jissorius(Gravenhorst) (Schneider, 1950), D. laetatorius (Fabricius) (Scott,1939), D. tetragonus (Thunberg) (Beirne, 1941), Promethus monticola(Vollenhoven) (Scott, 1939), Syrphoctonus signatus (Gravenhorst)(Scott, 1939), S. tarsaiorius (Panzer) (Scott, 1939; Beirne, 1941).The figiu-es of Scott are particularly good. Schneider figuresa labral sclerite in Diplazon Jissorius (Gravenhorst). This has notbeen seen in any specimen of Diplazon examined in the present studyand neither Scott nor Beirne figure this structure.Subfamily MetopiinaeFigures 48, 49Members of this subfamily are endoparasitic in Lepidoptera. Theparasites emerge from the pupae of the hosts.The epistoma is well sclerotized except in Triclistus; the pleurostomaand hypostoma are well sclerotized; the hypostomal spur is absentand the stipital sclerite extends dorsally to meet the hypostoma; thelabial sclerite is incomplete ventrally; on each maxUlary and labialpalp there is one large sensillum and one or several smaller sensilla;the silk press is well sclerotized; there is a lightly sclerotized plateventral to the press containing two sensilla; this plate may representthe dorsal part of the prelabial sclerite but is more probably theventral part of the silk press; the labral sclerite is absent; the mandiblesare relatively large and do not have teeth on the blade ; the antenna isdisc-shaped; the atrium of the spiracle is shallow; the closing apparatusof the spiracle is thin-walled and with a length approximately equal2'Of Scott (1939).
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 479
Of mmFigure 48.?Metopiinae, head sclerites: a, Metopius viicratorius (Fabricius); b, Triclistus\> curvator (Fabricius); c, Exochus scitulus Provancher, antenna not visible or. preparation.
^^Xl) antenna; 2, spiracle; 3, skin.)
480 PROCEEDINGS OF THE NATIONAL MUSEUM
O ? ! rnmFigure 49.?Metopiinae, head sclerites; Chorinaeus sp. (antenna not visible on preparation;2, spiracle; 3, skin.)
to the depth of the atrium, except in Metopius where the closing ap-paratus is thick-walled and with a length three to four times thedepth of the atrium; the skin is smooth with small spines and smallprojections.The head sclerites of the subfamily show a strong resemblance tothose of the Anomalinae. They also resemble the Pimplini and theIchneumoninae in having large toothless mandibles and a well-sclerotized epistoma and pleurostoma. These resemblances are pos-sibly associated with similar habits since all these groups emerge fromthe pupae of Lepidoptera. Larval Ket1. Epistoma incomplete dorsally TriclistusEpistoma complete dorsally 22. A lightly sclerotized plate is present lateral to each pleurostoma and hypos-toma 3A lightly sclerotized plate is not present lateral to each pleurostoma andhypostoma Chorinaeus3. A lightly sclerotized bar is present connecting the posterior pleurostomal pro-cesses across the dorsal surface of the food meatus ExochusA lightly sclerotized bar connecting the posterior pleurostomal processes notpresent MetopiusThe following were examined: Metopius micratorius (Fabricius)(fig. 48a), Triclistus curvator (Fabricius) (fig. 48b), Exochus alhijrons
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 481Cresson, E. scitulus Provancher (fig. 48c), Chorinaeus sp. (GCV)(fig. 49).Beirne (1941) figures Aletopius anxius Wesmael and Triclistus poda-gricus (Gravenliorst)
.
Subfamily OphioninaeThis subfamily has many characters resembling those of the Lissono-tinae and Mesoleiinae. As stated in the introductory keys to sub-families, it was found necessary to break up the Ophioninae intotribes in order to differentiate these from the two related subfamilies.Tribe CanapopleginiFigures 50-56This tribe includes many important endoparasites of economicpests. Most of the species attack lepidopterous larvae. Exceptionsinclude those of the genus Olesicampe parasitic on Tenthredinidae andDiprionidae, of Biolysia and Bathyplectes parasitic on Curculionidae,and of Pyracmon parasitic on wood-boring Coleoptera.The dorsal part of the epistoma is unsclerotized and the lateral partsare lightly sclerotized; the pleurostoma is lightly sclerotized; thehypostoma is long and well sclerotized; the hypostomal spur is short;the stipital sclerite is present and its lateral end has a plate-like expan-sion in many genera; the labial sclerite is longer than wide in mostgenera and the ventral part is lightly sclerotized in many genera; theprelabial sclerite is present and is Y-shaped in most genera; the labialsclerite and the prelabial sclerite differ in shape in different genera; themaxillary and labial palps each bear two sensilla, one large and onesmall, in most genera; the silk press is well sclerotized; the labralsclerite is absent; the mandible is of relatively moderate size and inmost genera the base is rather square and the blade slender ; in Pyrac-mon and Prochas the blade is broad; the antenna is disc-shaped; theclosing apparatus of the spiracle is very lightly sclerotized and adjoinsthe atrium; the skin has small projections and small setae, except inProchas, where the setae are equal in length to the blade of the man-dible.The following key to genera is not particularly satisfactory. Somegenera have distinctive characters, but within certain genera, thelarval characters of the species examined differ widely. This mightindicate that the classification of the adults is greatly in need of re-vision. One solution for the present stud}^ would have been to groupthe species examined on larval characters only, ignoring the relation-ships indicated by the U.S. Department of Agriculture's synopticcatalog. This has been done to a very limited extent. For example
482 PROCEEDINGS OF THE NATIONAL MUSEUM
?;;-4,-Ts?o-i-"
Figure 50,? Ophioninae:CampoplegIni, head sclerites: a, Pyracmon xanthognatha (Rohwer);B, Campoplex validus (Cresson); c, XantJiocampoplex nigroviaculatus (Cameron). (1,antenna; 2, spiracle; 3, skin.)
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 483
O- ! rrjmFigure 51.?OphIoninae:Campoplegini, head sclerites: a, Ideckihis nigriscafus Viereck-B, Castnarta eupitheciae Viereck; c, Charofs papilionis Ashmead. (1, antenna: 2, spiracle'3, skin.) '
484 PROCEEDINGS OF THE NATIONAL MUSEUM
0*1 m m
-^^i i--
FiGURE 52.?OphionInae:Campoplegini, head sclerites: a, Charops narangae (Cushman);B, Bathyplectes curculionis (Thomson); c, Biolysia tristis (Gravenhorst), antenna notvisible on preparation. (1, antenna; 2, spiracle; 3, skin.)
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 485
: " ^r
%
0-1 mmFigure 53.?Ophioninae:Campoplegmi; head sclerites: a, Campoletis oxylus (Cresson);B,Dusona vitticollis vitticollis (Norton); c, Nepiera benevola Gahan. (1, antenna; 2spiracle; 3, skin.)
486 PROCEEDINGS OF THE NATIONAL MUSEUM vol. no
^j./
0'\ mmFigure 54.?Ophioninae:Campoplegini. a, Phobocampe disparis (Vlereck), head sclerites;B, Horogenes comptoniellae (Viereck), head sclerites; c, Hyposoter pilosulus iProvancher),mandible. (1, antenna; 2, spiracle; 3, skin.)
ICHNEUMONID FINAL INSTAR LARVAE SHORT 487
O ? t m mFigure 55.?Ophioninae:CampoplegIni. a, Olesicampe pikonemae Walley, head sclerites(1, antenna; 2, spiracle; 3, skin); b, Olesicampe lophyri (Riley) (1, mandible; 2, labium);c, Holocremnus dandestinus (Holmgren), head sclerites (1, antenna; 2, spiracle; 3, skin.)
504675?59-
488 PROCEEDINGS OF THE NATIONAL MUSEUM
O ?! mm
0-1 mmFigure 56.?Ophionmae:Campoplegini, head sclerites: a, Benjaminia fuscipennis (Pro-vancher); b, Charopsimorpha unicincta (Ashmead); c, Prochas theclae Walkley, newgenus, new species. (1, antenna; 2, spiracle; 3, skin.)
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 489some species of Hyposoter are listed in a different part of tlie key fromothers. But the key is largely a compromise in that an attempt hasbeen made to fit the larval characters into a scheme of classificationbased on adult characters. A revision of the tribe in the light of bothlarval and adult characters would be the only satisfactory solution.Larval Key
1. Setae on body approximately equal in length to blade of mandible.Prochas Walkley, new genus 2*Setae on body much shorter than blade of mandible 22. Mandible as in figure 50a with no marked diflferentiation between base andblade PyracmonMandible with blade more slender than base 33. A lightly sclerotized plate is present lateral to each pleurostoma and hypo-stoma and extending dorsally to meet ventral half of antenna . Spudastica^*A lightly sclerotized plate, if present, not of this shape 44. A lightly sclerotized and lobed plate as in figure 54a present lateral to eachpleurostoma and hypostoma and not extending dorsally to meet ventralhalf of antenna PhobocampeA lightly sclerotized plate of this shape not present 55. A lightly sclerotized plate extends dorsally from pleurostoma across to meetventrolateral edge of antenna BenjaminiaA lightly sclerotized plate of this shape not present 66. Prelabial sclerite roughly triangular in shape with ventral part poorly devel-oped 7Prelabial sclerite Y-shaped with ventral part as well developed as dorsal parts97. Ventral part of prelabial sclerite extending to point just ventrad of labialpalps Charops narangae (Cushman)Charops ganges CushmanVentral part of prelabial sclerite not extending to point just ventrad of labialpalps 88. A lightly sclerotized plate present beneath ventral part of labial sclerite.BathyplectesA lightly sclerotized plate not present beneath ventral part of labial sclerite.Biolysia
i* In order that Dr. Short may refer to this gonus by a valid name a brief description Is given here. R. A,Cushman had set aside in the U.S. National Museum collection two black campopleglne specimens thathe had labelled as Prochas theclae, a manuscript name.Prochaa theclae, new genus, new speciesThis new genus is closely related to Charopsimorpha Viereck, 1912 but may be easily distinguished from itby the broader postpetiole, different abdominal sculpture, fully areolated propodeuin, and by unusual headcharacters for this gi-oup of the Campoplcgini. The type species, Prochas theclae, has the occipital carinameeting the hypostomal carina at the base of the mandible; has non-emarginate eyes (the Inner margin atmost only slightly sinuate); has the clypeus (pale in the male) protruding just before the apex and with theapex slightly rounded, and mandibles with flange on only the basal half of lower margin.Holotype female (USNM 64687), Trinidad, B.W.I., Aug. 6, 1943, Diego Martin. AUotype male (USNM),Trinidad, B.W.I., Nov. 14, 1941, Brasso. Both specimens were reared from Thecla empusa How. ou cacaoby E. McC. CaUan. Luella M. WalkleyEntomology Research DivisionU.S. Department of Agriculture? Of Bcirne (1941).
490 PROCEEDINGS OF THE NATIONAL MUSEUM vol.iio
9. Prelabial sclerite with ventral part broader than lateral parts of labial sclerite.Charops papilionis AshmeadPrelabial sclerite with ventral part not as broad as lateral parts of labialsclerite 1010. Lateral parts of epistoma broad and lightly sclerotized . . . HolocremnusLateral parts of epistoma not of this form 1111. Labial sclerite longer than wide ^^ 12Labial sclerite as wide or wider than long 1712. Ventral part of labial sclerite broad and well sclerotized . XanthocampoplexVentral part of labial sclerite not as above 1313. Ventral part of labial sclerite forming broad, lightly sclerotized plate and notdistinct from any lightly sclerotized membrane in ventral part of prelabialarea 14Ventral part of labial sclerite not forming broad, lightly sclerotized plate anddistinct from any sclerotized membrane in ventral part of prelabial area 2?1614. Prelabial sclerite not meeting broad ventral part of labial sclerite . . IdecthisCampoplex ^^Prelabial sclerite meeting broad ventral part of labial sclerite 1515. Ventral part of labial sclerite lightly sclerotized and pointed . . . DusonaHyposoter parogyiae (Viereck)Ventral part of labial sclerite as well sclerotized as lateral parts and morerounded Olesicampe lophyri (Riley)16. Ventral part of labial sclerite very lightly sclerotized; lateral part of stipitalsclerite about 1^2 times as broad as median part CampoletisVentral part of labial sclerite moderately sclerotized; lateral part of stipitalsclerite about twice as broad as median part HyposoterHorogenesOlesicampe pikoneniae Walley,Olesicampe euurae (Ashmead)17. Labial sclerite complete ventrally CharopsimorphaLabial sclerite incomplete ventrally 1818. Each lateral part of prelabial sclerite approximately equal in length to ventralpart CasinariaEach lateral part of prelabial sclerite one-half to one-third length of ventralpart NepieraThe following have been examined: Pyracmon xanthognatha (Roh-wer) (fig. 50a), Campoplex crassifemur (Thomson), C. depressusViereck, C. frustranae Cushman, C. hyalinus (Provancher), C. phthori-maeae (Cushman), C. polychrosidis Viereck, C. pyraustae Smith, C.rufijemur (Thomson), C. tosensis (Uchida), C. tricoloripes (Schmiede-knecht), C. validus (Cresson) (fig. 50b), Campoplex ^^. nr. inaequalipesCresson, Xanthocampoplex nigromaculatus (Cameron) (fig. 50c),Xanthocampoplex sp., Idechthis nigriscapus Viereck (fig. 51a), /.
2? In using this part of the key care should be taken to ensure that all of the prelabial region Is fully visiblein a preparation. In some species which have the ventral part of the labial sclerite lightly sclerotized thispart may become folded under the rest of the prelabium during mounting, with the result that the labialsclerite appears to be much shorter than it really is." Except Hyposoter parorgyiae (Viereck), where the prelabial sclerite meets the broad ventral part of thelabial sclerite.M Except Campoplex tosensis (Uchida), which can be recognized by the bubble-like appearance of theprelabial and labial sclerites.
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 491
canescens (Gravenhorst), Casinaria eupitheciae Viereck (fig. 51b),C. induhia (Morley), C. infesta (Cresson), C. tenuiventris (Graven-horst), Casinaria sp., Charops gauges Cushman, C. narangae (Cush-man) (fig. 52a), C. papilionis Ashmead (fig. 51c), Bathyplectes corvina(Thomson), B. curculionis (Thomson) (fig. 52b), B. exiquus (Graven-horst), Biolysia tristis (Gravenhorst) (fig. 52c), Campoletis oxylus(Cresson) (fig. 53a), Dusona glauca glauca (Norton), D. quehecensis(Walley), D. terehrator (Foerster), D. variabilis (Franklin), D. vitti-collis vitticollis (Norton) (fig. 53b), Nepiera benevola Gahan (fig. 53c),Phobocampe disparis (Viereck) (fig. 54a), P. flavipes (Provancher),Horogenes acutus (Viereck), H. aestivalis (Viereck), H. compressus(Cresson), H. comptoniellae (Viereck) (fig. 54b), H. eureka (Ashmead),H. obliteratus (Cresson), H. pterophorae (Ashmead), H. punctorius(Roman), Horogenes sp., Hyposoterfugitivus fugitivus Say, H.fugitivuspacificus Cushman, H. nigrolineatus (Viereck), H. parorgyiae (Viereck),H. pilosulus (Provancher) (fig. 54c), H. rubiginosus Cushman, Olesi-campe euurae (Ashmead), 0. pikonemae Walley (fig. 55a), 0. lophyri(Riley) (fig. 55b), Holocremnus clandestinus (Holmgren) (fig. 55c),H. ratzeburgi (Tschek), Benjaminiafuscipennis (Provancher) (fig. 56a),B. euphydryadis (Viereck), Charopsimorpha tibialis (Cresson), C.unicincta (Ashmead) (fig. 56b), Prochas theclae Walkley, new genus,new species (fig. 56c)
:
Pyracmon has a distinctive form of mandible with a relatively broadblade. Within the genus Campoplex, C. pyraustae Smith has a labialsclerite which is more rounded than in the other species examined,and in Campoplex sp. nr. inaegualipes Cresson the mandible has acurved but broad blade with a width equal to that of half the depthof the base. C. tosensis (Uchida) differs from the species figured inthat the prelabial sclerite meets the broad ventral part of the labialsclerite. Idechthis canescens (Gravenhorst) is basically similar to thespecies figured, but the enlargement on the lateral end of the stipitalsclerite is relatively smaller. The species of the genus Charops fallinto two groups: C. ganges Cushman being very like C. narangae(Cushman) (fig. 52a), and C. obtusus Morley as figured by Beirne(1941) being similar to C. narangae. Bathyplectes and Biolysia aredistinctive in the shape of the labial sclerite and in the triangular andlightly sclerotized prelabial sclerite. Horogenes, Hyposoter, andOlesicampe are basically similar. The labial sclerite is more roundedthan in figure 54b in Hyposoter fugitivus fugitivus Say and H.fugitivuspacificus Cushman. Also, in these two subspecies the lightly sclero-tized area between the base of the prelabial sclerite and the ventralpart of the labial sclerite is not present. The mandible of Hyposoterhas a small lobe dorsal to the blade. This is seen in a slight form inother Campoplegini, but is more pronounced in Hyposoter, especially
492 PROCEEDINGS OF THE NATIONAL MUSEUM vol. noin H. pilosulus (Provancher) (fig. 54c). In H. parorgyiae (Viereck)the region between the prelabial sclerite and the ventral part of thelabial sclerite has the form of a lightly sclerotized plate. In bothHorogenes and Hyposoter the labial sclerite has a small infolding ateach venterolateral edge. Olesieampe euurae (Ashmead) is very-similar to 0. pikonemae Walley in structure. In 0. lophyri (Riley) thelabial sclerite differs in shape from that of these two species in that theventral part is broad ; also the prelabial sclerite is short and the mandi-ble is distinctive in form, being relatively small with a rounded baseand a small, straight blade. Prochas theclae Walkley differs from otherCampoplegini in the length of the setae of the skin and the shape ofthe mandible; however, the head sclerites in general resemble thoseof the Campoplegini.The following are figured in the literature: Nemeritis hicingulataGravenhorst (Beirne, 1941), Campoplex alkae (EUinger and Sachtleben)(Baker, Bradley, and Clark, 1949; Goidanich, 1931), C. borealis(Zetterstedt) (Thorpe, 1930), C. crassifemur (Thomson) (Thompsonand Parker, 1930), C. cultrator Gravenhorst (Beirne, 1941), C. ensator(Gravenhorst) (Thorpe, 1930), C. mutabilis (Holmgren) (Thorpe,1930), C. rufifemur (Thomson) (Thorpe, 1930), C. validus (Cresson)(Tunberlake, 1912), Idechthis canescens (Gravenhorst) (Daviault,1930), Charops obtusus Morley (Beirne, 1941), Bathyplectes exiquus(Gravenhorst) (Benne, 1941), Spudastica kriechbaumeri (Bridgman)(Bemie, 1941), Phobocampe unicincta (Gravenhorst) (Bekne, 1941),Horogenes armillata (Gravenhorst) (Beirne, 1943), H. exareolatus(Ratzeburg) (Beirne, 1941), H. macrostoma (Thomson) (Roberti,1947), H. nana (Gravenhorst) (Thorpe, 1933), H. punctorius (Roman)(Baker, Bradley, and Clark, 1949), Horogeries sp. (Cameron, 1938),Horogenes sp. (Beirne, 1942), Hyposoter pilosulus (Provancher)(Tothni, 1922), H. tricolor (Ratzeburg) (Beirne, 1941), Holocremnusratzeburgi (Tschek) (Morris, Cameron, and Jepson, 1937), Balcarciabergi Brethes (Griot and Icart, 1948).Tribe CremastiniFigures 57, 58Members of this tribe are endoparasitic, mostly in microlepidop-terous larvae in leaf rolls and tunnels. Many of them frequent drierhabitats than is usual for the family.The tribe closely resembles the Campoplegini, although the headsclerites are, in general, more lightly sclerotized. Also, the hypostomalspur is longer, the lateral part of the stipital sclerite is not expanded,except in Eiphosoma where the expansion is small, and the labialsclerite is broader than in most Campoplegmi. In all species examined
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 493
O'l mm
Figure 57.?OphIoninae:Cremastini, head sclerites: a, Pristomerus vulnerator (Panzer);B, Xiphosomella stenomae Cushman; c, Zaleptopygus flavo-orbitalis (Cameron). (1,antenna; 2, spiracle; 3, skin.)
494 PROCEEDINGS OF THE NATIONAL MUSEUM vol. no
O -1 mm
O'l mmFigure 58.?Ophioninae:Cremastini, head sclerites: a, Cremastus ferrugineus Davis;B, Eiphosovia hatatae Cushman. (1, antenna; 2, spiracle; 3, skin.)
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 495the labial sclerite is incomplete ventrally. The skin is lightly sclero-tized with small projections and small setae.Larval Key
1. Each lateral part of the labial sclerite with a small projection towards themedian line EiphosomaEach lateral part of labial sclerite without small projection towards medianline 22. A very lightly sclerotized epistoma present . . . Zaleptopygus, CremastusEpistoma not sclerotized 33. Hypostoma bent in the middle of its length PristomerusHypostoma bent at point one third of length from median end . XiphosomellaPristomerus euryptychiae Ashmead differs from the drawing in figure57a in that there are two groups each of two sensilla on the labrum.Cremastus minor Cushman differs from the drawing in figure 58a inthat the ventral part of the labial sclerite is lightly sclerotized.It was not found possible to differentiate Zaleptopygus and Cremas-tus on larval characters.The following have been examined: Pristomerus austrinus (Townesand Townes), P. euryptychiae Ashmead, P. pacijicus appalachianusViereck, P. vulnerator (Panzer) (fig. 57a), Xiphosomella stenomaeCushman (fig. 57b), Zaleptopygus flavo-orhitalis (Cameron) (fig. 57c),Z. gallaecola (Cushman), Z. rosae (Cushman), Zaleptopygus sp.,Cremastus carpocapsae Cushman, C. epagoges Cushman, C. facilis(Cresson), C ferrugineus Davis (fig. 58a), G. forbesi Weed, C. minorCushman, Eiphosoma annulatum Cresson, E. hatatae Cushman (fig.58b), E. insularis (Viereck), E. texanum Cresson.The following are figured in the literature: Pristomerus vulnerator(Panzer) (Goidanich, 1931; Rosenberg, 1934), Zaleptopygus flavo-orhitalis (Cameron) (Bradley and Burgess, 1934), Cremastus interruptorGravenhorst (Thorpe, 1930; Beu-ne, 1941).Tribe TersilocLiniFigure 59This tribe, the larvae of which are endoparasites, resembles theCremastini and many Campoplegini in essential structure, but themandible is distinctive with its conical shape and small tooth at theapex. The head sclerites are slender and lightly sclerotized. As inmost Cremastini, the stipital sclerite has no lateral expansion. Thelabial sclerite is broader than long and is incomplete ventrally. Theventral part of the prelabial sclerite is absent and several large sensillaare present on the ventral edge of this sclerite. The maxillary andlabial palps are relatively large. The spu-acle is of the usual shape inthe Ophioninae with a lightly sclerotized closing apparatus adjoining
496 PROCEEDINGS OF THE NATIONAL MUSEUM
.^-,-_--,A-.Ol rnm ^Figure 59.?Ophioninae:Ters'ilochini, head sclerites: Tersilochus argentinensis (Blanchard)(antenna not visible on preparation; 2, spiracle; 3, skin.)the atrium. The skin has relatively long setae, approximately equalin length to one-third the length of the mandible, but the projectionson the skin are small.Tersilochus argentinensis (Blanchard) (fig. 59) and T. conotracheli(Riley) were examined. T. conotracheli is figured by Cushman (1916)and Tersilochus sp. by Beirne (1941).Tribe OphioniniFiGUUB GO A, BMembers of this tribe are endoparasitic in larger caterpillars, exceptthat Ophion bifoveolatus Brulle is known to parasitize larvae of Phyl-lophaga (Scarabeidae). Species of Ophion and Enicospilus are noc-turnal or crepuscular and are frequently attracted to lights.This is a distinctive tribe although it resembles other tribes of theOphioninae ui many basic features. The head sclerites are broadand moderately sclerotized. The stipital sclerite has a small lateralexpansion and a lightly sclerotized cardo is present. The ventralpart of the labial sclerite forms a broad plate. The prelabial scleriteis triangular in shape with the ventral part reduced. Numeroussetae are present on the labrum, on the maxilla lateral to the hypos-tomal spur and on the prelabial membrane and the labial sclerite.The mandibles are distinctive, being relatively small and with arounded base and a slightly or strongly curved blade. The antennais disc-shaped. The closing apparatus of the spiracle is lightlysclerotized and adjoins the atrium. The skin has very small setaeand small projections.
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 497
Ol mm
O -1 mm - v\^^"rc i >-2 3Figure 60?a, b, Ophioninae:0phlonlni, head scleriles: a, Ophion idoneum Viereck; b, Eni-cospilus arcuatus (Felt), c, Anomalinae:AnomaIini, head sclerltes, Anomalon sp., antennanot visible on preparation. (1, antenna; 2, spiracle; 3, skin.)
498 PROCEEDINGS OF THE NATIONAL MUSEUM
I 10-1 mm
0-1 mmFigure ^61.?Anomalinae:Gravenhorstiini, head sclerites: a, Aphanistes hyalinus (Norton),antenna not visible on preparation; b, Barylypa insidiator (Foerster), antenna not visibleon preparation; c, Labrorychus analis (Say). (1, antenna; 2, spiracle; 3, skin.)
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 499
O -1 rn m
O ? 1 mm
O ? 1 mmFigure 62.?Anomalinae: Gravenhorstiini, head sclerites: a, Atrometus clavipes (Davis);B, Agrypon sp.; c, Blaftocampus nigricornis (Wesmael). (Antenna not visible on prepara-tion; 2, spiracle; 3, skin.)
500 PROCEEDINGS OF THE NATIONAL MUSEUM vol. no
I 1O-t mm
0-1 mmFigure 63.?Anomalinae:Therioninl, head sclerites: a, Therion circumflexum (Linnaeus);B, Heteropelma fulvicorne Townes, antenna not visible on preparation. (1, antenna;2, spiracle; 3, skin.)
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 501Larval Key1, Mandible with blade slightly curved OphionMandible with blade strongly curved so that the tip points dorsally.EnicospilusThe following were examined: Ophion ancyloneura Cameron,0. hilineatus Say, 0. idoneus Viereck (fig. 60a), 0. tityri Packard,Enicospilus amerieanus (Christ), E. arcuatus (Felt) (fig. 60b), E.glabratus (Say), E. horsfeldi Cameron, E. purgatus (Say), E. texanus(Ashmead), and Enicospilus spp.In Enicospilus amerieanus the blade of the mandible, although ofthe Enicospilus form, is not so strongly curved as in figure 60b. Alightly sclerotized plate is present on the ventral edge of the labrumof some species of Enicospilus. This shoidd not be confused withthe suspensorium of the hypopharynx which is also visible in severalspecies.The following are figured in the literature: Thyreodon atricolor(Olivier) (Cushman, 1947), Enicospilus macrurus (Drury) (Beirne,1941), E. purgatus (Say) (Cushman, 1947), Enicospilus sp. (Moutiaand Courtois, 1952), and Ophion idoneus Viereck (Cushman, 1947).Subfamily AnomalinaeFigures 60c-63This endoparasitic group usually has been placed as a tribe of theOphioninae. The larval characters of those species examined differmarkedly from the characters of the Ophioninae and the group hastherefore been treated as a separate subfamily. The form of thelabial sclerite is generally similar in the Anomalinae and Ophioninaeand, although this might indicate some sort of general relationshipbetween the two groups, the form of the remaining sclerites and themandibles differs sharply.The epistoma, pleurostoma, and hypostoma are broad and wellsclerotized; the hypostomal spur is absent; the stipital sclerite curvesdorsally from the labial sclerite to meet the hypostoma; the labialsclerite is relatively slender and is incomplete ventrally except inAnomalon where the ventral part is moderately sclerotized, andin Heteropelma where the ventral part is very lightly sclerotized; themaxillary and labial palps each have two sensilla, one large and onesmall, except in Anomalon where the two sensilla are approximatelyequal in size, the dorsal being flat and the ventral peglike; the silkpress is sclerotized; a lightly sclerotized prelabial sclerite which lacksa ventral projection is present in some genera; the labral sclerite isabsent, but large sensUla which are grouped in various patterns arepresent on the labral area; setae are reduced and labral and prelabialsetae appear to be absent except in Anomalon; the mandibles arelarge with relatively straight blades which lack teeth except in
502 PROCEEDENGS OF THE NATIONAL MUSEUM vol. noAnomalon, and the blade of eacli mandible is well sclerotized; theantenna is disc-shaped ; the closing apparatus of the spiracle is lightlysclerotized and adjoins the atrium; the skin has small projectionsand small setae.The larval characters of the Anomalinae are strikingly like thoseof the Metopiinae. The larvae of the two subfamilies may be distin-guished by the presence of setae on the prelabium of the Metopiinaeand the absence of these setae in the Anomalinae except Anomalon,a genus having so many special features as to be readily recognizable.The reduction of the labial sclerite and hypostomal spur in theAnomalinae, Metopiinae, and Ichneumonmae might be correlatedwith the relatively slight cocoon spun by these endoparasites. Inthe head of the final instar larva of Xorides muscles are present whichinsert on the labial sclerite (Short, 1952, p. 41, fig. 8a). The con-traction of these muscles tilts forward the dorsal end of the pre-labium with the opening of the silk glands. In this action the labialsclerite rotates on the extremities of the stipital sclerites. Thelabial sclerite is thus held so that movement can take place in onlyone plane. The spurs of the hypostomae, which articulate with thestipital sclerites, hold the maxillae rigid. The spinning of the cocoonhas been observed in Xorides and the region of the prelabium contain-ing the opening of the silk glands was tilted forward during thisprocess. It is therefore possible that the reduction of a cocoon isaccompanied by a reduction of the muscles which evert the dorsalend of the prelabium and a reduction of the labial sclerite and h3rpos-tomal spur. One objection to this suggestion is that the Pimplini,which emerge from the pupa of a lepidopterous host and have onlya slight cocoon, have a well developed hypostomal spur and labialsclerite. However the stipital sclerite is reduced and this mightbe associated with the reduction of the cocoon since, when beingeverted, the labial sclerite rotates on the stipital sclerite.Larval Key
1. Blade of mandible with teeth; setae on prelabium AnomaliniBlade of mandible without teeth; setae absent from prelabium .... 22. Width of epistoma along entire length and width of pleurostoma along entirelength equal to at least half length of mandible TherioniniWidth of epistoma or part of width of pleurostoma less than length of man-dible GravenhorstiiniOphionellini ^'Tribe AnomaliniFigure 60cThe general form of the head sclerites, spiracles, and sldn placesAnomalon with the genera of the tribes Gravenhorstiini and Therionini;? Of Cushman (1947).
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 503but it does not appear to be a close relationship, a conclusion whichWalkley (in litt.) has also reached from study of the adults. Anomalondiffers from the other Anomalinae examined in that the blade of themandible bears distinct teeth; there are setae on the prelabium; andthe ventral part of the labial sclerite, although not as well sclerotizedas the lateral parts, is nevertheless distinctly sclerotized. It is alsopossible that the hypostomal spur might be represented in Anomalonby a small projection from the anteroventral part of the hypostoma.Anomalon therefore can be considered to have an isolated positionwithin the Anomalinae. The larval habits also distinguish this genusfrom other Anomalinae in that larvae of Elateridae appear to be theusual hosts, whereas the hosts of the other Anomalinae examined werelepidopterous.Anomalon sp. (60c) was examined. A. ejuncidum Say is figured byCushman (1947). Tribe OphionelliniOphionellus foutsi (Cushman) is figured by Cushman (1947). Thisfigure is not suflficiently detailed to allow the Ophionellini to be dis-tinguished from the Gravenhorstiini.
Tribe GravenhorstiiniFigures 61, 62Larval Key1. Labral sensilla arranged in two separate groups AtrometusLabral sensilla arranged in single line 22. When head sclerites mounted flat on slide then posterior ends of hypostomaeextend to point approximately level with ventral end of labial sclerite . . 3When head sclerites mounted flat on slide then posterior ends of hypostomaedo not extend to point level with ventral end of labial sclerite 43. Width of pleurostoma at anterior pleurostomal process approximately equalto two-thirds length of mandible AphanistesWidth of pleurostoma at anterior ]:ileurostomal process much less than two-thirds length of mandible Labrorychus4. Hypostoma with sclerotized expansion along entire dorsal edge . . BarylypaHypostoma without sclerotized expansion along entire dorsal edge .... 55. Length of blade of mandible less than half width of base and arising fromventral surface of base BlaptocampusLength of blade of mandible approximately equal to half width of base andarising from middle of base AgryponThe foUomng have been examined: Aphanistes hyalinus (Norton)(fig. 61a), Barylypa insidiator (Foerster) (fig. 61b), Labrorychus analis(Say) (fig. 61c), L. prismaticus (Norton), Labrorychus sp., Atrometusclavipes (Davis) (fig. 62a), Agrypon sp. (fig. 62b), Blaptocampusnigricornis (Wesmael) (GCV) (fig. 62c).504675?59 8
504 PROCEEDINGS OF THE NATIONAL MUSEUM vol. ii?The following are figured in the literature: Trichomma enecator(Rossi) (Rosenberg, 1934), Aphanistes armatus (Wesmael) (Beirne,1941), Blaptocampus nigricornis (Wesmael) (Beirne, 1941).Tribe TherioniniFigure 63Larval Key1. Ventral part of labial sclerite lightly sclerotized HeteropelmaVentral part of labial sclerite not sclerotized TherionThe following have been examined: Therion morio (Fabricius),T. circumflexum (Linnaeus) (fig. 63a) , Heteropelma fulvicorne Townes(fig. 63b). Therion morio (Fabricius) is figured by Cushman (1947).Interrelationships between the SubfamiliesAlthough in many cases the larval characters suggest interrelation-ships which are very similar to those which are believed to be shownby the characters of the adults, there are certain discrepancies.Some similar adults, such as the Pimplini and Ephialtini, have verydifferent larvae. These differences may be correlated with the factthat the larvae of the Pimplini are endoparasitic while those of theEphialtini are ectoparasitic. The larval characters of the Ephialtiniand similar tribes of the Pimplinae resemble those of other ectopara-sites such as the Tryphoninae and Cryptinae rather than the Pimplini.There are certain structural features which appear to be connectedwith whether the larva is an ectoparasite or an endoparasite. Theantenna in most ectoparasites is papilliform. In most endoparasitesit is reduced and disc-like. The mandible is toothed in most ecto-parasites where teeth are necessary for holding on to the host andfor piercing the host skin. In most endoparasites the mandible iswithout teeth. The labral sclerite is present in most ectoparasitesand absent in most endoparasites. The epistoma and the labralsclerite are rarely present together, except in the Tryphoninae, wherethe epistoma is slender. It is difficult to suggest a reason for this.The anterior retractor muscles of the labrum insert on the medianpart of the labral sclerite (Short, 1952, p. 39, fig. 7b). It is notlikely that the labral sclerite could brace the cranium in any way asa substitute for the epistoma. The epistoma is well developed inlarvae with powerful mandibles.The closing apparatus of the spiracle adjoins the atrium in mostendoparasites, whereas in ectoparasites it may adjoin the atrium or besituated some distance from the atrium. There is no obvious explana-tion for this. It is generally assumed that the spiracles are open inendoparasites in the final instar larva, which is carnivorous, feeding on
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 505
f\
?
'\-<ij-r\?rv^ A?r\ ^ /\ r\OlmmFigure 64.?Cryptinae:Hemitelini, head sclerites: Atractodes sp. (1, antenna; 2, spiracle;3, skin.)the tissues of the host and hberating air from the tracheae. If thespiracle is open there is possibly some biological advantage in havingthe closing apparatus situated close to the atrium. If one function ofthe closing apparatus is to prevent the entry of body fluids of the hostinto the tracheal system, then it is best situated to perform this func-tion when it adjoins the atrium. If, however, such a precaution werenecessary, one would more readily expect to find hydrofuge structuresat the opening of the tracheal system, as in many aquatic insects.The setae of the sldn of endoparasites are reduced.It should be noted that the Cryptinae, which contain both ecto-parasites and endoparasites of prepupae and pupae, show larvalcharacters which are relatively uniform within the group.Just as some similar adults have different larvae, so do some differentadults, such as the Metopiinae and Anomalinae, have similar larvae.These similarities may be correlated with larval habits. The Meto-piinae, Anomalinae,^'^ Ichneumoninae, and Pimplini all have large,
30 Except Anomalon.
506 PROCEEDINGS OF THE NATIONAL MUSEUM vol. notoothless mandibles mth a corresponding development of the epistomaand pleurostoma. In the Metopiinae, Anomalinae, and Ichneumoninaethe hypostoma is also well developed. In the Pimplini the hypostomais reduced, but the hypostomal spur is well developed. The hypostomalspur is absent in the Metopiinae, Anomalinae, and Ichneumoninae.The labial and stipital sclerites are, except in the Pimplini, relativelypoorly developed. The reduction of these sclerites might be corre-lated with the relatively slight cocoons spun by these endoparasites(see section on Anomalinae)
.
In the species examined of the Metopiinae, Anomalinae,^^ Ichneu-moninae, and Pimplini, development takes place in, or is completed in,the pupa of a lepidopterous host. The Campoplegini, which are endo-parasites of larvae, have a different type of head structure with theepistoma absent and the labial and stipital sclerite relatively welldeveloped. With regard to the degree of development of these scleritesit is significant that many Campoplegini emerge from the host larva tospin a well developed cocoon, although some species of Hyposoter andBenjaminia pupate within the host larva.It cannot be claimed that all Ichneumonidae which emerge from thepupa of the host, or even from the pupa of a lepidopterous host, willhave a larval head of similar form. The Cryptinae have a head struc-tm-e which is very different from that of the Metopiinae, Anomalinae,Ichneumoninae, and Pimplini, Also, larval habits are not constant.Mr. J. F. Perkins (in litt.) has directed my attention to some rearedspecimens of Trichomma occisor Habermehl with a quite well developedcocoon and to an Ophion in which the cocoon is spun within the hostpupa, which remains adhering to the outside of the cocoon. Thorpe(1930) has observed that the ectoparasite Ephialtes rujicollis (Graven-horst) spins a light and irregular cocoon, yet when reared in a gelatincapsule usually does not spin a cocoon. But it does appear that in mostMetopiinae, Anomalinae, Ichneumoninae, and Pimplini there is someconnection between the form of the larval head and the habits of thelarva. It is thus possible that convergence in larval characters asso-ciated with a similarity in larval habits might explain the similarity ofthe Metopiinae and Anomalinae.From the standpoint of larval characters alone, the following inter-relationships are suggested among the subfamilies of the Ichneu-monidae. The Metopiinae and Anomalinae are related. The Ophi-oninae, Mesoleiinae, and Lissonotinae are also related subfamilies.Similarly, but to a lesser extent, there appears to be some degree ofrelationship between the Tryphoninae, Cryptinae, and the tribes ofthe Pimplinae other than the Pimplini and Acaenitini. The Ichneu-moninae show some likeness to the Orthopelmatinae. The Adelogna-thinae, Collyriinae, Plectiscinae, Diplazoninae, and Mesochorinae are
" Except Anomalon, which pupates within the larvae of Elateridac.
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 507
all isolated subfamilies. The Pimplini and Acaenitini are isolatedtribes showing some degree of relationship to each other and to theremaining tribes of the Pimplinae.There was thought to be no point in attempting to construct a familytree.Relationship between the Ichneunionidae and BraconidaeThe tribe Xoridini of the Pimplinae has a type of mandible whichresembles that of the subfamily Braconinae of the Braconidae. TheBraconinae possess the most generalized larval structure of theBraconidae. Since the larval structure of the Xoridini is also gener-alized, it is possible that this tribe connects the Ichneumonidae to theBraconidae. There is a similarity in larval habit as well as in larvalstructure since many primitive ichneumonids and braconids areparasites of woodboring insects (see Brues, 1921).ReferencesAyyar, p. N. Krishna1943. Biology of a new ichneumonid parasite of the Amaranthus stemweevil of South India. Proc. Indian Acad. Sci. (b), vol. 17, pp.27-36.Baker, W. A.; Bradley, W. G.; and Clark, C. A.1949. Biological control of the European corn borer in the United States.U.S. Dep. Agr. Techn. Bull. 983, 185 pp.Batjmann C. von1933. Zur Kenntnis der Metamorphose von Ephialtes manifestator L.,Coleocentrus excitaior Poda und Echthrus reludator L. (Hym. Ichn.).Zool. Anz., vol. 102, pp. 143-155.Beirne, B. p.1941. A consideration of the cephalic structures and spiracles of the finalinstar larvae of the Ichneumonidae (Hym.). Trans. Soc. BritishEnt., vol. 7, pp. 123-190.1942. Notes on some lepidopterous pests on fruit trees, and their parasites,in Ireland during 1941. Econ. Proc. Roy. Dublin Soc, vol. 3,pp. 107-118.1942a. The biology and control of the Larch-Shoot Moth, Argyresthialaevigatella H.-S. Econ. Proc. Roy. Dublin Soc, vol. 3, pp. 130-149.1943. The biology and control of the small ermine moths {Hyponomeutr spp.)in Ireland. Econ. Proc. Roy. Dublin Soc, vol. 3, pp. 191-220.Blunk, H.1952. Zur Kenntnis der Hyperparasiten von Pieris brassicae L. Pt. 5:Hemtteles simillimus sulcatus. Die Metamorphose. Zeitschr. Ang.Ent., vol. 33, pp. 421-459.Bradley, W. G., and Burgess, E. D.1934. The biology of Cremastus flavo-orbilalis (Cameron), an ichneumonidparasite of the European corn borer. U.S. Dep. Agr. Techn. Bull.441, 16 pp.
508 PROCEEDINGS OF THE NATIONAL MUSEUM vol. noBkown, N. R.1947. Studies on the parasites of the spruce budworm, Archips fumiferana(Clem.). 2. Life historjf of Glypia fumiferanae (Viereck) (Hy-menoptera, Ichneumonidae). Canadian Ent., vol. 78, pp. 138-147.Brues, C. T.1921. Correlation of taxonomic affinities with food habits in Hymenoptera,with special reference to parasitism. Amer. Nat., vol. 55, pp.134-164.Cameron, E.1938. A study of the natural control of the pea moth, Cydia nigricana Steph.Bull. Ent. Res., vol. 29, pp. 277-313.1950. The biology and economic importance of Alomya debellator (F.), aremarkable parasite of the swift moth, Hepialis lupulinus (L.).Bull. Ent. Res., vol. 41, pp. 429-438.1951. On the identity of an ichneumonid parasite of Hepialis lupulinus (L.).BuU. Ent. Res., vol. 41, p. G37.Chrystal, R. N., and Skinner, E. R.1931. Studies on the biologj^ of Xylonomus hrachylabris Kr. and X. irrigator?., parasites of the larch longhorn beetle, Tetropium gabriele Wiese.Forestry, vol. 5, pp. 21-33.Clancy, D. W.1946. The insect parasites of the Chrysopidae (Neuroptera). Univ. Cali-fornia Publ. Ent., vol. 7, pp. 403-496.Cushman, R. a.1916. Thersilochus conotracheli, a parasite of the plum curculio. Journ.Agr. Res., vol. 6, pp. 847-855.1947. A generic revision of the ichneumon-flies of the tribe Ophionini.Proc. U.S. Nat. Mus., vol. 96, pp. 417-482.CuSHr.IAN, R. A., AND ROHWER, S. A.1921. Holarctic tribes of the subfamily Ichneumoninae (Pimplinae). Proc.U.S. Nat. Mus., vol. 69, pp. 379-396.Daviault, L.1930. Notes biologiques sur Newcritis canescens Grav. et sur la morphologiede ses divers stades. Rev. Path. Veg., vol. 17, pp. 82-93.DOWDEN, P. B.1941. Parasites of the birch leaf-mining sawfly {Phyllutoma nemorata)
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U.S. Dep. Agr., Techn. Bull. 757, 56 pp.Given, B. B.1944. The anatomy of the final larval instar of Diadromus (Thyraella)collaris Grav. (Ichneumonidae), witii notes on str\ictural changesduring the prepupal and pupal stages. Trans. Roy. Soc. NewZealand, vol. 74, pp. 297-301.GOIDANICH, A.1931. Gli insetti predatore e parassiti della Pyrausla nubilaHs Hubn. Boll.I.ab. Ent. Bologna, vol. 4, pp. 77-215.Griot, M., and Icart, A.1948. Observaciones sobre Balcarcia bergi Brethes parasito del "bicho decesto." Rev. Inv. Agr. Buenos Aires, vol. 2, pp. 197-204.Imms, a. D.1918. Observations on Pimpla pomorum Ratz., a parasite of the appleblossom weevil. Ann. Appl. Biol., vol. 4, pp. 211-217.
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 509Itawa, K.1950. Biology of ichneumon parasites of bag-worms in Japan, I. Trans.Kansai Ent. Soc, vol. 15, pp. 35-47.Kloet, G. S., and Hincks, W. D.1945. A check list of British insects. 483 pp.Manbval, H.1936. Nouvelles notes siir divers hym^noptferes et leurs larves. Rev.Frangaise Ent., vol. 3, pp. 18-32.Meyer, H.1922. On the morphology of the larvae of some parasites of the familyIchneumonidae. Rep. Bur. Appl. Ent. Leningrad, vol. 2, pp. 25-39.Morris, K. R. S.1937. The prepupal stage in Ichneumonidae, illustrated by the life-historyof Exenierus abruptorius, Thb. Bull. Ent. Res., vol. 28, pp. 525-534.Morris, K. R. S.; Cameron, E.; and Jepson, W. F.1937. The insect parasites of the spruce sawfly {Diprion polytomum Htg.)in Europe. Bull. Ent. Res., vol. 28, pp. 341-393.MOUTIA, L. A., AND COURTOIS, C. M.1952. Parasites of the moth-borers of sugar-cane in Mauritius. Bull. Ent.Res., vol. 43, pp. 325-359.Nielsen, E.1923. Contributions to the life-history of the pimpline parasites {Poly-sphinda, Zaglyptus, Tromatobia) . Ent. Medd., vol. 14, pp. 137-205.1935. A third supplementary note upon the life histories of the Poly-sphinctas. Ent. Medd., vol. 19, pp. 191-215.1936. The biology of Homonoius sanguinolenlus Fabr. Ent. Medd., vol.19, pp. 385-404.Roberti, D.1947. Le oplocampe del Susino. I, Hoplocampe flava (L.). Boll. Lab.Ent. Agr. Portici, vol. 7, pp. 41-92.Rosenberg, H. T.1934. The biology and distribution in France of the larval parasites ofCydia pomonella L. Bull. Ent. Res., vol. 25, pp. 201-256.Salt, G.1931. Parasites of the wheat-stem sawfiy, Cephus pygmaeus Linnaeus, inEngland. Bull. Ent. Res., vol. 22, pp. 479-545.Sauer, H. F. G.1939. Biologia de Calliephialtes dimorphus Cushm. (Hym.: Ichn.) uminterresante parasita primario da Plaiyedra gossypiella (Saunders).Arch. Inst. Biol. (Def. Agr. Anim.). Sao Paulo, vol. 10, pp. 165-192.Schneider, F.1950. Die Entwicklung des Syrphidenparasiten Diplazon fissorius Grav.(Hym. Ichneum.) in uni-, oligo-, und polyvoltinen Wirten und seinVerhalten bei parasitarer Aktivierung der Diapauselarven durchDiplazon pectoratorius Grav. Mitt. Schweizerischen Ent. Ges.,vol. 23, pp. 22-44.Scott, E. I.1939. An account of the developmental stages of some aphidophagousSyrphidae (Dipt.) and their parasites (Hymenopt.). Ann. Appl.Biol., vol. 26, pp. 509-532.
510 PROCEEDINGS OF THE NATIONAL MUSEUM vol. iioShort, J. R. T.1952. The morphology of the head of larval Hymenoptera with specialreference to the head of Ichneumonoidea, including a classifica-tion of the final instar larvae of the Braconidae. Trans. Roy. Ent.Soc. London, vol. 103, pp. 27-84.1953. A grouping by larval characters of some species of the genus Apanteles(Hymenoptera: Braconidae). Bull. Ent. Res., vol. 44, pp. 327-332.SlLVESTRI, F.1941. Contribuzioni alia conoscenza degli insetti dannosi e del loro sim-bionti. VI. La folena brumale o la brumale {Operophtera brumataL.). Boll. Lab. Ent. Agr. Portici, vol. 5, pp. 61-120.SiMMONDS, F. J.1947. The biology of Phytodietus pulcherrimus (Cress.) (Ichneumonidae,Tryphoninae) parasitic on Loxostege sticticalis L. in North America.Parasitology, vol. 38, pp. 150-156.1948. The biology of the parasites of Loxostege sticticalis L. in NorthAmerica. IV. Cryptus inornatus Pratt (Ichneumonidae, Cryp-tinae). Proc. Roy. Ent. Soc. London (a), vol. 23, pp. 71-79.Snodgrass, R. E.1935. Principles of insect morphology, ix -1-667 pp.Spbyer, W.1926. Ptmpla pomorum Ratz. (Ichneumon.), der Parasit des Apfelbliiten-stechers, Anthomus pomorum L. Arb. Biol. Abt. (Anst.-Reichs.)Berlin, vol. 14, pp. 231-257.Thompson, W. R., and Parker, H. L.1930. The morphology and biology of Eulimneria crassifemur, an importantparasite of the European corn borer. Journ. Agr. Res., vol. 40,pp. 321-345.Thorpe, W. H.1930. Observations on the parasites of the pine-shoot moth, Rhyacioniabuoliana Schiflf. Bull. Ent. Res., vol. 21, pp. 387-412.1933. Notes on the natural control of Coleophora laricella, the larch case-bearer. Bull. Ent. Res., vol. 24, pp. 271-291.TiMBERLAKE, P. H.1912. Experimental parasitism, a study of the biology of Limneriumvalidum (Cresson), Techn. Ser. U.S. Bur. Ent., vol. 19, pp. 71-92.TOTHILL, J. D.1922. The natural control of the faU webworm (Hyphantria cunea Drury)in Canada. Techn. Bull. Dep. Agr. Canada, vol. 3.Townes, Henry, and Townes, Marjorie1951. Family Ichneumonidae. In Muesebeck, et al., Hymenoptera ofAmerica north of Mexico?Synoptic catalog. U.S. Dep. Agr.Monogr. No. 2, pp. 184-409.Van Emden, F. I.1955. In Gordon, Importance of larval characters in classification. Nature,vol. 176, p. 911.1957. The taxonomic significance of the characters of immature insects.Ann. Rev. Ent., vol. 2, pp. 91-106.
ICHNEUMONID FINAL INSTAR LARVAE?SHORT 511Walkley, Luella M.1956. A tribal revision of the brachycyrtine wasps of the world (Cryptinae-Ichneumonidae). Proc. U.S. Nat. Mus., vol. 106, pp. 315-329.1958. Family Ichneiunonidae, in Krombein, ed., Hymenoptera of Americanorth of Mexico?Synoptic catalog. U.S. Dep. Agr. MonographNo. 2, suppl. 1, pp. 36-62.WiGGLESWORTH, V. B.1954. The physiology of insect metamorphosis, viii+152 pp.WiSHART, G.1949. The biology of Melanichneumon rubicundus (Cress.) (Hymenoptera,Ichneiunonidae). Canadian Ent., vol. 80, pp. 118-137,
II. S ?OVEIINMENT PRINTIHS OFFICEiltlt