SMITHSONIAN INSTITUTION
MUSEUM OF NATURAL HISTORY
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UNITED STATES NATIONAL MUSEUM BULLETIN 279
Larval Taxonomy of theTroginae in North Americawith Notes on Biologiesand Life Histories(Coleoptera: Scarabaeidae)
CHARLES W. BAKERDepartment of Biological SciencesBoise State College
SMITHSONIAN INSTITUTION PRESSWASHINGTON, D.C.1968
PUBLICATIONS OF THE UNITED STATES NATIONAL MUSEUMThe scientific publications of the United States National Museum include twoseries, Proceedings of the United States National Museum and United StatesNational Museum Bulletin.In these series are published original articles and monographs dealing withthe collections and work of the Museum and setting forth newly acquired factsin the fields of anthropology, biology, geology, history, and technology. Copiesof each publication are distributed to libraries and scientific organizations andto specialists and others interested in the various subjects.The Proceedings, begun in 1878, are intended for the publication, in separateform, of shorter papers. These are gathered in volumes, octavo in size, with thepublication date of each paper recorded in the table of contents of the volume.In the Bulletin series, the first of which was issued in 1875, appear longer,separate publications consisting of monographs (occasionally in several parts)and volumes in which are collected works on related subjects. Bulletins areeither octavo or quarto in size, depending on the needs of the presentation.Since 1902, papers relating to the botanical collections of the Museum have beenpublished in the Bulletin series under the heading Contributions from the UnitedStates National Herbarium.This work forms number 279 of the Bulletin series. Frank A. TaylorDirector, United States National Museum
U.S. GOVERNMENT PRINTING OFFICEWASHINGTON : 1968
Contents PageIntroduction 1Acknowledgments 3Literature Review 4Systematics 6Methods and Materials 9Collection of Specimens 9Preservation of Specimens 10Rearing of Immature Stages 11Preparation and Study of Specimens 12Terminology 13Illustrations 14General Biology 14General Description of Immature Stages 16Life History 17Keys to the Known Third (Final Stage Larvae) 19Key to the Genera 19Key to the Known Third Stage Larvae of 7 ro.v 19Key to the Known Third Stage Laivae of Omorgus 21Generic Description of Trox Larvae 21Species Descriptions of Trox Larvae 25Generic Description of Omorgus Larvae 39Species Descriptions of Omorgus Larvae 42Summary 53Literature Cited 55Appendix. Symbols Used on Figures 59Illustrations 61V

Larval Taxonomy of the Troginaein North America With Notes on Biologiesand Life Histories(Goleoptera: Scarabaeidae)
'
By Charles W. Baker ^
IntroductionThe subfamily Troginae of the Scarabaeidae is represented by threegenera in North America: Trox^ Omorgus^ and Glaresis, of whichOmorgus is restored to generic status in this study. Only those speciesof Trox and Omorgus which occur in North America are treated inthis bulletin. No attempt has been made to separate the species out-side of North America into Trox s. st. and Omorgus. The subfamilycontains one other genus, Cryptogenius, which is restricted to SouthAmerica.The genus Glaresis is known from eight species in North America.During this study numerous adults were collected in Oregon, but allattempts to rear the larvae were unsuccessful. The biology of thisgenus is unknown, and the placement of Glaresis within the Troginaehas been questioned by Crowson (1955).The adults and larvae of Trox and Omorgus can be characterized asfacultative animal necrophages. Records indicate that they feed on theremains of a great many terrestrial animals as well as certain aquatic
1 Modified from a thesis submitted in partial fulfillment of the requirementsfor the Ph. D. degree. Department of Entomology, Oregon State University, Cor-vallis, Greg.2 Department of Biological Sciences, Boise State College, Boise, Idaho.Technical Paper No. 2279, Oregon Agricultural Experiment Station1
2 U.S. NATIONAL MUSEUM BULLETIN 2 79forms which are washed ashore. The larvae of several species havebeen reported feeding on the eggs of the migratory locusts in Asia,Africa, and South America (Denier, 1936; Hayward, 1936; Gardner,1946; RofTey, 1958). The two genera have a nearly worldwide distri-bution, being more common in desert and semidesert regions. Forty-two species of Trox and Omorgus are known at present in North America(Vaurie, 1955, and Howden and Vaurie, 1957). In this report thelarvae of 24 species are described, 18 for the first time, and the pertinentmorphological structures are illustrated.At the commencement of this study the larvae of most of the majorgroups within the Scarabaeoidea were fairly well known. The morecomprehensive works include the following : Aphodiinae Qerath, 1 960)
;
Coprinae (Ritcher, 1 945c) ; Gcotrupinae (Ritcher, 1 947, and Howden,1955); Melolonthinae (Ritcher, 1949, and Boving on Phyllophaga only,1942); RuteUnae (Ritcher, 1945a); Dynastinae (Ritcher, 1944);Cetoniinae (Ritcher, 1945b); and Hayes (1929) and Boving andCraighead (1931), who were concerned primarily with the taxa abovethe species level.Each of the above subfamilies has also been treated by Ritcher (1966)in his comprehensive work on the scarabaeoid larvae of North America,along with additional sections on the Glaphyrinae, Hybosorinae,Pleocominae, Acanthocerinae, and Troginae and the families Luca-nidae and Passalidae. Ritcher's treatment of the Troginae is the mostextensive to date for North America, and includes figures for thelarvae of four species of Trox.This study of the immature stages was undertaken to help clarifythe taxonomic status of the Troginae. The placement of the Troginaewithin the Scarabaeidae has varied with different workers. Certainworkers, among them Edwards (1949) and Crowson (1955), havegiven the group family status. This writer is in agreement with those,among them Arnett (1960), Vaurie (1962), and Ritcher (1966), whowould retain the group as a subfamily within the Scarabaeidae. Com-parative studies on the larval musculature and larval nervous systemare currently in progress and should aid in the systematic placement ofthe various subfamilies.^ The high degree of syminetry in the structuresof the epipharynx and hypopharynx of Trox and Omorgus are indicativeof the generalized condition. This is in agreement with the findingsof Sharp and Muir (1912), who would derive the male aedeagus of allthe scarabaeid subfamilies from that of the Troginae.Prior to this study the larvae of six species of Trox and Omorgus wereknown from North America. Four of these six species ha\'e been reared
' Personal communication with Dr. F. H. Butt, Route 1 , Box 47C, Friday Harbor,Wash.
LARVAL TAXONOMY OF THE TROGINAE IN NORTH AMERICA 3in this investigation along with those of 18 other species. Certain speciesare distinguished in the adult stage only by characters of the maleaedeagus. This, plus the fact that as many as six species may occurtogether under a single carcass (Spector, 1943), necessitated laboratoiyrearings to associate the adults and larvae accurately.
AcknowledgmentsThe writer is especially grateful to Dr. Paul O, Ritcher who suggestedthe topic, provided the assistantship, and gave most liberally of histime and energies in the capacity of major professor.The v/riter also wishes to express his gratitude to the following in-dividuals and institutions for their assistance during the course of thisstudy: O. L. Cartwright and D. M. Anderson, U.S. National Museum,for the exchange of adult specimens and the loan of adults and im-matures; Mrs. P. Vaurie, American Museum of Natural History,for the loan and exchange of adult specimens; L. J. Bottimer, Kerr-ville, Tex., Dr. M. A. Cazier and M. A. Mortenson, Portal, Ariz.,Dr. G. Cottam, Rob and Bessie Welder Wildlife Foundation, Sinton,Tex., Dr. R. O. Drummond and Dr. O. H. Graham, EntomologyResearch Division, U.S. Department of Agriculture, Kerrville, Tex.,Dr. R. I. Gara, Boyce Thompson Institute Forest Research Laboratory,Beaumont, Tex., E. L. Pond, San Pedro Ranch, Carrizo Springs, Tex.,and V. D. Roth, Southwest Research Station, American Museum ofNatural History, Portal, Ariz., for the hospitality and assistance thatthey rendered during the collecting trip through Arizona, New Mexico,and Texas in the summer of 1964; J. F. Cornell, R. K. Eppley, K.Goeden, D. L. Mays, G. E. Osgood, Dr. R. L. Rabb, Dr. S. Radinov-sky. Dr. W. P. Stephen, and J. R. A. Willard for assistance in thecollection of adults and larvae; L. J, Bottimer, Dr. R. I. Gara, N.McFarland, Dr. F. D. Parker, and Dr. L. A. Stange for their assistancein the collection and shipment of numerous live adults to the wTiter;Dr. N. Virkki, University of Puerto Rico, Agricultural ExperimentStation, for his studies of the spermatogenesis and chromosomes ofTrox and Omorgus; Dr. O. Zethner-Moller and W. H. G. Schallig fortheir kind assistance in the translation of foreign papers; P. Schillingand the Genetics Department for their help in attaining insecticide-free foodstuffs for the beetles; David R. Smith for his assistance on thecollecting trip during the summer of 1964; Dr. J. D. Lattin, Dr. C. H.Martin, Dr. F. H. Butt, and other members of the Department ofEntomology, Oregon State University for their advice and encourage-ment.
4 U.S. NATIONAL MUSEUM BULLETEST 2 79This study was supported by National Science Foundation grantsGB 3586 and G 17935, and by other funds from the Oregon Agri-cultural Experiment Station.
Literature Review
The first description of a Trox larva was evidently that of Waterhouse(1836) who described the larva of Trox arenarius Fabricius, synonymof T. scaler (L.), in a paper on the larvae and pupae of coleopterousinsects.Schiodte (1874) described a single larva of Trox sabuloms L. at greatlength, but according to Meinert (1895) this larva was not that ofsabulosus. Meinert had collected this larva himself along with a singleimago in Algeria and had loaned it to Schiodte. Meinert believed itto be the larva of T. fabricii Reiche.The larva of T. scaler (L.) was again described by Xambeau (1892)who later also added a description of the egg and general biology(1895). The larva of T. perlatus Goeze was described by Xambeau(1896) in detail, again without any figures,Fabre (1903) described the habits of the larvae and adults of T.perlatus and noted their importance in the conversion of dead animalmaterial.The larvae of T. hispidus Pontoppidan and T. scaler (L.) weredescribed by Henriksen (1925). He characterized the larva of T.hispidus as possessing a black head capsule and with spinules only onthe first fold of abdominal segment seven. The larva of T. scaler hada reddish head capsule and with spinules on all three folds of abdominalsegment seven.Hayes (1929) was the first to describe the larva of a species of Troxin North America. He figured the lateral aspect of the larva, thecephalic aspect of the head capsule, the epipharynx, and the leftprothoracic spiracle of what was probably T. unistriatus Beauv.Boving and Craighead (1931) briefly characterized larvae of thegenus Trox in a couplet of a key to the families and subfamilies of theScarabaeoidea. They were the first to recognize the presence of bothbiforous and cribriform spiracles within the genus. They noted thatlarvae of T. scaler (L.), T. aequalis Say, and T. unistriatus Beauv.possessed biforous spiracles and the larva of T. oligonus Loom is (syno-nym of Omorgus texanus LeConte) possessed cribriform spiracles.The egg, larva, pupa, and adult of T. costatus Wied. were describedby Leefmans (1932) from material reared from adults collected in theMampu Cave in South-Celebes. He experimented with various diets,achieving success with bat guano or dead insects, or a mixture of both.
LARVAL TAXONOMY OF THE TROGINAE IN NORTH AMERICA 5The larva of the nearly cosmopolitan T. suberosus Fab. was brieflydescribed by Sim (1934) from North America. Denier (1936) figuredthe head capsule and mandibles of T. suberosus from South America.Hayward (1936) in the same publication provided photographs ofthe egg, larva, pupa, and adult of T. suberosus. Denier and Haywardwere reporting on the significance of T. suberosus as a predator of theeggs of the migratory locust.Van Emden (1941) included the larvae of T. scaber and T. hispidusin a key to the British lamellicornia larvae. He figured the left antennaof T. scaber and noted that in his larvae the spinules did not occurposterior to the fold of abdominal segment seven which bears thelong setae. He further noted that whereas he regarded this as the secondfold, Henriksen (1925) evidendy considered it as the third fold. Thearea in contention above is referred to in this paper as dorsal lobe two(DL2), and is the median lobe of abdominal segment seven, beyondwhich the spinules do not occur in this species.The larvae of T. scaber and T. hispidus also were included by Paulian(1943) in a key to the scarabacoid larvae of France, wherein he sep-arated the larvae of these species in the same manner as van Emden(1941). His figure of the epipharynx of T. scaber is somewhat different,however, from that of my material.Gardner (1946) briefly described the larva of T. procerus Haroldfrom India. The larva of T. procerus was described in greater detail byvan Emden (1948). Van Emden also described the larva of T. costatusVVied. and figured the third stage larva of T. procerus and spiracles ofT. scaber^ T. procerus, and T. costatus. He illustrated the supportingstruts beneath the respiratory plates since they appeared to be differentin the species he had at hand. In this study the struts have beenfound to be too variable to allow separation at the species level.Peterson (1951) characterized Trox larvae at the generic level forNorth America and commented on the general biology of the group.Paulian (1956) again separated the larvae of Trox from those ofother scarabaeids of France. He figured the entire larva, epipharynx,and terminal segments (ventral aspect) of T. perlatus F.The larva of T. sabulosus L. was briefly characterized by Panin(1957), and the terminal abdominal segment (posterior view) andprothoracic leg figured. His figures are so distincdy different from allknown figures of Trox larvae that it is quite possible that they areactually those of some other genus.Roffey (1958) described the larva and biology of T. procerus Har.in great detail. From his figures, however, it would appear thatRoffey was actually working with more tlian one species.The most comprehensive treatment of Trox larvae to date is thatof Ritcher (1966), wherein he has presented a key for the separationof the larvae of the suberosus group as recognized by Erichson (1847)
6 U.S. NATIONAL MUSEUM BULLETIN 2 79and LeConte (1854). He is the first to have recognized the differencein the pattern of the stridulatory teeth on the maxillae of the twogroups. Incertae SedisPerris (1877) described the larva of Trox hispidus Laichart. Hefigured the left maxilla, left mandible (dorsal aspect), right mandible(lateral aspect), left antenna, posterior segments (posterior view),and leg of T. hispidus. The figures, however, are not very detailed.
SystematicsA comprehensive monograph on the adults of the genus Trox inNorth America was published by Vaurie in 1955. Vaurie separated thespecies of Trox into five groups: scaber, terrestris, tuberculatus, untstriatus,and suberosus. A checklist of the species grouped according to Vaurieis presented in table 1. Species whose larvae are now knov/n aremarked with an asterisk.Two additional species were described by Howden and Vaurie in1957. These species were T. floridanus and T. howelli, and they areincluded in their respective groups in table 1.Other major treatments of the adults of Trox include the following:Palearctic Region (Balthasar, 1936), Africa (Haaf, 1953), Africa andAsia (Haaf, 1954a), Australia (Haaf, 1954b), and South America(Vaurie, 1962).Vaurie (1955) recognized that the suberosus group was quite distinctfrom the other four groups in North America and presented a tablelisting ten characters which distinguished the adults of this group fromthose of the other groups.On the basis of the larval systematics and recent work on themorphology and cytogenetics of the adults, the writer has restoredOmorgus to generic status to include those species in Vaurie's suberosusgroup in North America. The genus Omorgus was first proposed byErichson (1847). Trox suberosus Fabricius was later designated byLacordaire (1856) as the type. LeConte (1854) followed Erichson inthis separation, placing 1 1 species from North America in the genus.Subsequent workers, however, considered Omorgus as synonymous withTrox^ as a subgenus of Trox, or as the suberosus group within the genusTrox. The characters supporting the above separation are presentedin table 2. These are in addition to those characters listed by Vaurie(1955) in her monograph on the adults. Distinguishing characters arepresent in all life stages : egg, larva, pupa, and adult. The writer makes
LARVAL TAXONOMY OF THE TROGINAE IN NORTH AMERICATable 1 .
?
List of species of Trox in Korik America after Vaurie ( 1955) and Howdenand Vaurie ( 1957) . The species of the suberosus group have been placed in the genusOmorgus as a result of this and other recent investigations. Species whose larvaeare now known are marked by an asterisk, and the third stage larva of each isdescribed in this study.
1
.
scaber group*T. scaber (Linnaeus)*T. aequalis SayT. affinis Robinson*T. fascifer LeConteT. striatus MelsheimerT. laticollis LeConte*T. atrox LeConte
2. terrestris groupT. hamatus RobinsonT. spinulosus simi RobinsonT. s. spinulosus Robinson*T. s. dentibius Robinson* T. foveicollis HaroldT. terrestris Say* T. frontera Vaurie
3. tuberculatus group*T. sonorae LeConteT. contractus Robinson*T. robinsoni WaurieT. gemmulatus HornT. acanthinus Harold*T. tuberculatum (DeGeer)T. floridanus Howden andVaurie*T. plicatus Robinson
no attempt at this time to separate the species on a worldwide basis.It may well be that there are more than two genera worldwide.The characters of the immature stages of the genus Trox lend supportto Vaurie's recognition of the scaber and terrestris groups for the adults.Larvae of the scaber group have an epipharynx with four smallersensory spots distad of the two lai'ger, setiferous sensory spots on thesensory area of the haptomerum and only two sensory spots distad ofthe slightly arching, transverse row of sensory spots on the pedium.The terrestris, tuberculatus, and unistriatus groups have only two smallersensory spots distad of the two larger, setiferous sensory spots on thesensory area of the haptomerum and four sensory spots distad of theslightly arching, transverse row of sensory spots on the pedium. The
4. unistriatus group*T. variolatus Melsheimer*T. sordidus LeConteT. capillaris Say* T. unistriatus Beauvois
5. suberosus groupT. tytus RobinsonT. howelli Howden and Vaurie*T. suberosus Fabricius* T. rubricans Robinson* T. carinatus LoomisT. tomentosus Robinson* T. monachus Herbst*T. fuligiriosus RobinsonT. scabrosus Beauvois*T. asper (LeConte)* T. punctatus Germar
'^T. infiatus LoomisT. tesselatus (LeConte)T. nodosus Robinson*T. texanus (LeConte)T. umbonatus (LeConte)*7'. scutellaris Say
U.S. NATIONAL MUSEUM BULLETIN 279Table 2.
?
Morphological differences between Trox and Omorgus{characters pertain to larvae unless otherwise noted)
.
Trox1. Spiracles biforous.2. Maxillae with curved, diffusedouble row or curved patchof stridulatory teeth.3. Chromosomes metacentric.^4. Antenna with prominent sensorycone on distal end of segment 2.
5. Frontocylpeal suture indistinct.6. Extruded rectal membrane withelongate, continuous sclerotizedareas.7. Left mandible with two teeth (S3and S4) on median borderproximad of scissorial notch.
8. Each anterior angle of frons withone seta.9. Tibiotarsus with two whorls ofsix setae each.
10.
11,
12.13.
14.
15.
Prothorax with two small laterallobes.Prothorax without setae on dorsal,nonsclerotized area betweenshields.DL2 of mesothorax without setae.Haptolachus without sclerotizedsense cone.Glossa with four or five setae ondorsal aspect.Rows of phobae on proximal areaof hypopharynx curving medi-ally to join at base.
16. Pupa with two terminal claws onprothoracic legs.
1 7. Adult female reproductive systemwith sbi short ovarioles on eachside.
Omorgus
1
.
Spiracles cribriform.2. Maxillae with single, straight rowof stridulatory teeth.
3. Chromosomes acrocentric.4. Antenna without sensory cone;with slighdy concave sensoryarea.5. Frontocylpeal suture distinct.6. Extruded rectal membrane withoval, isolated sclerotized areas.
7. Left mandible with three teeth(S3, S4, and S5) on medianborder proximad of scissorialnotch.8. Each anterior angle of frons withthree or more setae.Tibiotarsus with terminal whorl ofsix setae plus about 8 to 22scattered setae proximad ofwhorl.Prothorax with single large laterallobe.
1 1 . Prothorax with setae on dorsal,nonsclerotized area betweenshields.DL2 of mesothorax with setae.Haptolachus with sclerotizedsense cone.Glossa with eight or more setae ondorsal aspect.Rows of phobae on proximal areaof hypopharynx not curvingmedially to join at base, widelyseparated at base.Pupa without terminal claws onprothoracic legs.Adult female reproductive systemwith three long ovarioles oneach side.
9.
10
17
? Testes from males of known ages were used by Dr. N. Virkki, University ofPuerto Rico, Agricultural Experimental Station, for the studies of the chromosomes.
LARVAL TAXONOMY OF THE TROGINAE IN NORTH AMERICA 9
terrestris group is distinguished by having six sensory pegs on the distalportion of the terminal segment of the antenna (figs. 44 and 47). Theother three groups have five sensory pegs and one long sensory seta(figs. 45 and 46).It appears that Vaurie's tuberculatus and unistriatus groups are closelyallied on the basis of larval characteristics. The larvae of these groupscould not be separated one from the other, and several larvae of thetuberculatus group are so similar that they have been brought out to-gether in the same key couplet.The larvae of the genus Omorgus are generally much larger than thoseof TVo.v, and with a few exceptions are much more setiferous. Certainof the species are quite distinct and easily recognized. Others, however,are so similar that the writer cannot separate them by reliable keycharacters.Species groups within the genus Omorgus are evident on the basis oflarval characters. 0. monachus and 0. fuliginosus are the only species topossess spinules but no setae on DL 1 of the first four abdominal segments.All other species possess both. 0. rubricans and 0. texanus are distin-guished from the other species by the large concavity mediad of the eye-spot and by the transverse row of caudally directed phobae at the baseof the smaller distal portion of the hypopharynx. The larvae of theother six species of Omorgus are apparently much more homogeneous.Methods and MaterialsCollection of SpecimensThe four species of Trox and Omorgus which are known to occur inOregon were collected at black light and a method for rearing thelarvae was worked out during the summer of 1963. The majority ofthe remaining species ( 1 5) were collected at black light or at carcasseson an extended trip through Arizona, New Mexico, and Texas duringJune and July of 1964. Other species were collected by interestedworkers and airmailed to Corvallis, Oreg., for rearing. Two shipmentsof specimens were received from South America, but all specimensdied en route.* Additional preserved larvae were obtained from theUnited States National Museum and Dr. P. O. Ritcher.The black light setup consisted of one 15-watt General ElectricF15T8-BL tube placed on each side of a cloth sheet which was sus-
* Transportation or shipment of living specimens was done with State and Federalpermission.
10 U.S. NATIONAL MUSEUM BULLETIN 279pended on a portable metal stand at a height of 5 feet. One additionalsheet was placed flat on the ground on each side of the vertical sheet tosilhouette the smaller specimens. The lights were powered by a 12-volt model 50-167 Terado Power inverter connected to a 12-volt carbattery.A trapline of mammal and bird carcasses was set out in June andJuly of 1964. The trapline commenced at Nogales, Ariz., and extendedeastward through southern Arizona, New Mexico, and central Texas,terminating at the town of Uvalde, Tex. The return tinp to check thetrapline was made during the last two weeks of July. Additional car-casses along the trapline and in eastern and southern Texas wereinvestigated. The carcasses proved to be more productive than theblack light for the collection of adult Trox and Omorgus.The carcass was turned first and all readily visible specimens ofTrox retrieved. The debris beneath the carcass and the soil to a depthof about 18 inches were passed through window screening (14- by18-inch mesh). The material that failed to pass was spread out on apiece of canvass sheeting in the sun. The heat from the sun served to
"activate" the death feigning, dirt-coated adults so that they could bedistinguished from the debris.Representative adults and larvae were dropped into KAA solutionin the field or placed in individual salve tins for rearing or later fixation.Larvae of Omorgus were placed one to a tin since they are pungacious,whereas several larvae of Trox, especially the smaller species, could beplaced in one tin. The adults that were later used for laboratoryrearings were placed in Gerber baby food jars (140-ml. size) withperforated screw-cap lids. Each jar was about two-thirds filled withscreened sand and a small amount of food. The number of specimensper jar varied from about 10 for those 10 to 12 mm. long to about 50of the 5- to 7-mm. length. The jars were stored in styi'ofoam coolerscontaining a 2-quart can of ice which was insulated by 1 inch of foldednewspaper. This arrangement maintained a temperature of about 60to 70 degrees Fahrenheit within the cooler. About 1,000 live adultswere returned to Corvallis by this method.
Preservation of SpecimensThe larvae were preserved by two methods. In the first method thelarvae were placed in a solution of KAA (one part kerosene, one partglacial acetic acid, nine parts 95-percent ethyl alcohol) for 48 hoursand then transferred to 95-percent ethyl alcohol for storage. In thesecond method the larvae were placed in gently boiling water for3 minutes after which the beaker was removed from the heat and thecontents allowed to cool. When cool, the larvae were transferred to
LARVAL TAXONOMY OF THE TROGINAE IN NORTH AMERICA 1170-percent ethyl alcohol for storage. Best results with KAA wereobtained with recently moulted larvae. Late third stage larvae ofOmorgus usually shriveled instead of expanding when placed in KAA.Best results with boiling were obtained with larvae which had ceasedfeeding but had not yet become prepupae. The digestive tract ofactively feeding larvae often burst when the larvae were boiled, re-leasing the gut contents into the hemocoel. This produced a blackishspecimen, whereas the desired state is straw yellow to white.During fixation the anal area of most specimens becomes greatlyexpanded, exposing the lining of the rectum. The pattern of thesclerotized areas on this inflated, membranous lining of the rectum isquite different for Trox and Omorgus (figs. 50 and 52).Rearing of Immature StagesThe method used for rearing the larvae was adapted from thatpreviously used by Ritcher.^ Individual rearings were canned out withall species that could be confused on the basis of external morphology.This necessitated the sexing of specimens, since only two species aresexually dimorphic. The specimen was inactivated with carbon dioxideand placed under a binocular stereomicroscope. A pair of No. 5jeweler's forceps was used to open the urogenital orifice so that thegenitalia could be viewed. After sexing, the females were placed inseparate rearing containers.The rearing containers varied in size from a pint jar to a gallon jardepending on the size of the species. The jar was about two-thirdsfilled with damp, screened sand overlaid with food. The food consistedof a mixture of cow hair, deer hair, sheep's wool, rabbit hair and skin,and pheasant, quail, and dove feathers and skin. Great care had to beexercised to insure that the food source was free of insecticide. Thejar was wrapped with a black plastic sleeve that could be removed tocheck for eggs or larval burrows against the sides or bottom. Thejars were capped to keep out pests such as dermestids and tineids and tomaintain a high level of humidity.The eggs and larvae were removed at about 14-day intervals toindividual 2-ounce salve boxes. A representative portion of the Figeneration was preserved as larvae. The suspected identity of the fe-male was then confirmed by dissection of the male genitalia of adultsof the Fi generation.Individual larvae were reared in salve boxes filled with damp,screened sand with a small amoimt of food on one side. The develop-
^ Personal communication with Dr. P. O, Ritchcr wherein he described themethod he devised for the rearing of Trox larvae after observing how easily Dr.M. A. Czizier reared the larvae of one Southwestern species.285-935?68 2
12 U.S. NATIONAL MUSEUM BULLETIN 2 79ment of these larvae was checked periodically. It was found that thedevelopment was retarded, however, whenever the larvae were dis-turbed. Also, larvae left in the jars developed more rapidly than thoseplaced in the salve boxes. All rearings were carried out at roomtemperature.
Preparation and Study of SpecimensA binocular stereomicroscope with an ocular micrometer was usedfor the head capsule measurements. All measurements were made onspecimens submerged in alcohol. The greatest width of the head cap-sule was usually found to be at the eyespots or just posterior to theeyespots. The measurements are presented under each species descrip-tion with LI indicating first stage larva, LII indicating second stagelarva, and LIII indicating third stage larva. The majority of thedescriptive work ^vas done using a binocular stereomicroscope andmagnifications of 10X to 90X. A binocular compound microscopewas used to observe the details of structures such as the macrosensillaand antennal sensory pegs at magnifications of lOOX and 430X.Permanent whole mount slides of the antennae, hypopharynx,epipharynx, and maxillae were made for all species. The dissectedstructures usually were mounted directly from 70-percent ethyl alco-hol into Hoyer's mounting medium. Three small pieces of modelingclay were placed about the mounting medium in a triangle, and thecover slip placed on top of them. Pressure was then carefully applied tothe cover slip until the clay particles were flattened to a level wherethe cover slip was in close contact with the mounted material. Heavilypigmented or sclerotized structures were partially cleared in a solutionof hot, 10-percent KOH. These structures were removed to 70-percentethyl alcohol for several hours before mounting in Hoyer's.
Formula for Hoyer's Mounting Medium50 grams distilled water30 grams gum arable (clear crystals)200 grams cliloral hydrate20 grams glycerinThe ingredients should be mixed atroom temperatui'e in the above sequence.
It is unfortunate that many characters of taxonomic importance arelocated on the mouthparts of scarabaeid larvae since these areas aresubject to considerable abrasion. The reader is cautioned to take intoconsideration the fact that these structures may be broken, grounddown, or otherwise damaged in specimens of any instar which have
LARVAL TAXONOMY OF THE TROGINAE IN NORTH AMERICA 13
not recently moulted. The epipharynx and hypopharynx of manyTrox and Omorgus evidenced areas which had been so damaged.Often many dissections were necessary to find an undamaged epi-pharynx or hypopharynx. TerminologyThe terminology used in this report is essentially that employed byBoving (1936 and 1942) and Ritcher (1966). Where necessary a fewadditional terms have been used to facilitate the description of certainstructures and areas.The term "fused phobal mass" is used to denote the large, coalescedgroup of phobae located on each side of the pedium slightly anteriorto the tormae (fig. 2).The terms "subtorma" and "subapotorma" have been used to aidin the description of the hypopharynx. In each case the prefix "sub"has been affixed to the term used for a similar structure occurring onthe epipharynx. The prefix "sub" is used as these structures occur onthe dorsal surface of the submentum and ventral to similar structuresof the epipharynx.The term "subtorma" refers to the heavily sclerotized, transverse,curved process located near the proximal border of the hypopharynx.The subtormae of Trox and Omorgus are nearly symmetrical and havestrongly produced anterior and posterior projections at their outermargins. The subtormae are usually joined medially (figs. 10, 12,and 19).The term "subapotorma" refers to the heavily sclerotized processextending forward from the subtorma on each side mediad of thelongitudinal row of inwardly directed, closely set phobae of the hypo-pharynx (figs. 10, 12, and 19).The various lobes of the thorax and abdomen of the larvae have beenassigned names in this dissertation which differ from those generallyemployed in the past. Most workers have adapted the terminologynormally used for the sclerites of the adult insect thorax for use on thelarvae. Terms such as "prcscutum," "scutum," "scutellum," et cetera,have been used to refer to the diff"erent lobes of the segments of thethorax and abdomen of soft bodied larvae. This writer concurs withButt, however, in the usage of a simplified terminology for the larvaedistinct from that employed for the well-defined sclerites of the adults.?Butt in his work on the larval musculature of the Scarabaeoidea hasrestricted his approach to a recognition of lobes and of the folds whichset off these lobes. He has recognized the following for the abdominalsegments of the larvae: dorsal lobe one (DLl), dorsal lobe two (DL2),
8 Personal communication with Dr. F. H. Butt.
14 U.S. NATIONAL MUSEUM BULLETIN 2 79dorsal lobe three (DL3), and spiracular lobe (SL) (figs. 33 and 35).I have followed the above designation plus the following: laterallobe one (LLl), lateral lobe two (LL2), and lateral lobe three (LL3)for the three main lobes of the lateral area (figs. 33 and 35) ; and ventrallobe one (VLl), ventral lobe two (VL2), and ventral lobe three (VL3)for the three main lobes of the ventral region (fig. 28).In addition I have designated three subdivisions of DL3 on abdominalsegments one through six as DL3a, DL3b, and DL3c (fig. 33). Thesame terminology has been applied to the lobes of the thorax with theexception that there are usually only one or two such lobes per segmenton the thorax. IllustrationsThe figures were done with the aid of a squared grid in the ocularof a binocular stereomicroscope, using a Bausch and Lomb micro-projector, or freehand for those wliich were diagrammatic. Sclerotizedareas are indicated by stippling and the heavier the degree of sclerotiza-tion or pigmentation, the heavier the stippling. The degree of pig-mentation of the different areas was found to vary direcdy with thedegree of sclerotization.Broken lines on the figures of the epipharynx are used to indicate azone of transition in texture. Broken lines on the thoracic and ab-dominal figures denote secondary folds, whereas solid lines demarkthe primary folds of the different segments.
General Biology
Adults and larvae of Trox and Omorgus usually are found associatedwith animal remains (insects, fish, amphibians, reptiles, birds, mam-mals). They are commonly found as one of the last visitors of mammaland bird carcasses, or in the nests of birds and burrows of mammals,especially those in which there is an accumulation of fur or feathers.Vaurie (1955) in her monograph on the group included a section onbiology and information on the individual species where known.The adults of the North American species vary in size from about5 mm. to 19 mm. Most species have rough dorsal surfaces, and theyare usually covered with a crusty induement consisting mainly ofparticles of mud plus small pieces of debris from the media in whichthey live. At least a portion of this induement is attained as the teneraladults make their way from the pupal cells to the soil surface. Whendisturbed, the adults rapidly deflex the head and pull all the legs tightagainst the body in such a way that neither head nor legs are visiblefrom above. In this position and protectively covered as they are by
LARVAL TAXONOjVIY OF THE TROGINAE IN NORTH AMERICA 15the induement, the adults look very much like small clods of soil or apiece of the carcass or surrounding debris. The adults of some specieswill remain motionless like this for as long as an hour; T. atrox, how-ever, will move again within 2 or 3 minutes.The larger species, especially those of Omorgus, are usually associatedwith carcasses, whereas the smaller species, particularly those of thescaber group, are more often found in nests or burrows. Certain speciesapparently are found only in nest and burrow habitats. Hicks (1959)lists over 100 records of Trox spp. taken in bird's nests on a world-wide basis.The carcass-feeding forms appear to prefer dried carcasses thathave been reduced to skin, dermal derivatives, and bone. Thesecarcasses are particularly attractive after a heavy rain. This is dueperhaps to the increased odor produced by the wet carcass. Heavyrains also insure the presence of sufficient soil moisture for the de-velopment of the larvae in the soil beneath the carcass. As manyas five species of Trox and Omorgus have been collected by the writerbeneath a single carcass. The larger species were observed feedingon the hooves, skin, hair, and tendons, whereas the smaller speciesappeared to be associated with the hair and smaller remains.The females of the larger species generally burrow to a greaterdepth to lay their eggs than do females of the smaller species. A femaleof the small T. scaber deposits her eggs at a depth of about 1.0 to 3.0mm.; a female of the very large 0. texanus will burrow to a depth ofabout 6.0 to 10.0 inches for oviposition. The eggs are usually de-posited in groups of about three or four. The species laying very largeeggs may lay only one or two eggs at a time. The soil about the eggsapparently is specially treated by the female since it evidences aslightly different consistency.The larvae burrow vertically to the surface shortly after hatchingand commence to feed. The larvae are capable of rapid forward orbackward movement within their burrows, and when disturbed theyrapidly retreat to the bottoms of their burrows. The larvae pass throughthree instars having a total duration of about 4 weeks. The activethird instar usually burrows slightly deeper before constructing thepupal cell. Nest inhabiting species are known to construct pupal
"cocoons" within the walls of the nest (Robinson, in litt., cited in Vaurie,1955), utilizing debris and hair to form the wall of the "cocoon."Trox scaber was observed to do this in the laboratory when liberalamounts of hair were intermixed in the soil of the rearing container.The pupal stage averages about 9 to 15 days. The callow adultsremain in their pupal cells for at least 2 to 3 days during which timethey undergo hardening and darkening processes. Some speciesprobably pass the winter or summer within the pupal cell. Othersevidendy emerge to feed before hibernating or aestivating.
16 U.S. NATIONAL MUSEUM BULLETIN 2 79There is probably only one generation per year, with the adult asthe usual overwintering stage. It is possible that some species alsooverwinter as tliird instar larvae. For example, the writer received agroup of T. plicatus from N. McFarland which were collected on August5, 1963, near Portal, Ariz. Larvae reared from these adults did notpupate until April 1 964.The timing of the life cycle appears to vary with the species andclimatic conditions. Those species occurring in Oregon appear to berestricted to spring and early summer in their reproductive activities.Certain Southv/estern species are active during mid and late summer,but others such as T. frontera appear to have an early spring activityperiod and then oversummer as quiescent adults deep within the soil.It appears that spermatogenesis starts late in the adult life of Troxand Omorgus. '^ Mating of these beetles probably occurs, therefore, atthe onset of their next period of activity; early spring for those speciesoverwinterinsr as inactive adults.
General Description of Immature StagesThe immature stages consist of the following: egg, first stage larva,second stage larva, third stage larva, and pupa. The eggs are soft andshining milk white when first deposited, but decrease in luster withadvancing development. As with the eggs of other scarabaeids, the eggsof Trox and Omorgus expand in size after oviposition. They vary in sizefrom 1.10 mm. by 0.85 mm. for T. scaber to 4.0 mm. by 7.0 mm. for 0.texanus at a time shortly before hatching. The eggs of Trox retain theirspherical shape during development, but those of Omorgus take on areniform shape late in their development (fig. 23).First stage larvae have the fewest setae per given area of all threelarval stages. Second stage larvae have many more setae per givenarea, but still slightly fewer than the definitive number. Figures 16, 17,and 18 show the relative sizes of the three instars and their generalform. The larvae vary in color from white to straw yellow, with thecolor becoming more pronounced with age. Color is most easily as-certained in late third stage larvae which have voided the contentsof their alimentary tracts. The larvae of Trox and Omorgus are quitevariable even within the species with respect to body length. A tentativerange for body length may be arrived at, however, if one multiplies thehead width of the Omorgus species by a factor of 3.5 and 5.0 and thehead width of the Trox species by a factor of 4.5 and 7.5.
' Personal coinuiuiiication from Dr. N. Virkki, University of Puerto Rico, Agri-cultural Experimental Station, Februai'y 14, 1964.
LARVAL TAXONOMY OF THE TROGINAE IN NORTH AMERICA 17The larvae of Trox and Omorgus have a large, strongly pigmentedcranium which varies in color from orange, red, or brown to dark redbrown or black. The cranium is slightly reticulate posteriorly andslightly rugose anteriorly and bears a small number of setae in a well-defined pattern. The cranium also is strongly pitted in some species.The sclerotized shield of the prothorax is usually of a color similar tothat of the cranium.The larvae bear two specialized structures which are probably eggbursters on DLl of the mesothorax and metathorax. The bursters arethorn-like sclerotized projections bearing a short seta on the posteriorside near the base (fig. 15). They are located on each side of the dorsalmedian line slightly anterior to the transverse row of setae. The burstersare larger on the metathorax and they are generally larger on larvaeof Trox than on larvae of Omorgus. The egg bursters are present insecond and third stage larvae in a much reduced condition.The pupae are of the exarate type (figs. 32 and 34) and are sexuallydimorphic. The ventral aspect of abdominal segment eight in thefemales has two lobes flanking a slightly depressed median area (fig. 13).The ventral aspect of abdominal segment eight of the males has twolateral lobes flanking a median lobe (fig. 14), The setal pattern anteriorto the lobes is also slightly difl'erent for the males and females (figs. 1
3
and 14). Pupae of the two genera are separable in that the more slenderprothoracic legs of Trox bear a pair of terminal claws which are lackingon the stouter prothoracic legs of Omorgus (figs. 30 and 31).
Life HistoryThe following life history was worked out for Trox scaber (L.) in thelaboratory, at room tempeature. The female from which all the larvaewere reared was collected on April 26, 1965, at black light about 10miles north of Corvallis, Oreg., by the writer.This female was placed in a pint jar two-thirds filled with screenedsand which was overlaid with about one-half inch of hair and feathers.The female deposited a total of 11 eggs during the first 7 days ofcaptivity. These were deposited in groups of three and four at 2- to 3-day intervals. Egg production then decreased to an average of three tofour eggs about every 5 days during the next 16 days. It then decreasedagain in July and ceased altogether about July 15, 1965. A total of58 eggs and larvae was retrieved from the container.The female oviposited at a depth of about 1 to 3 mm. beneath thefood source. The larvae hatched about 8 to 9 days after oviposition.First stage larvae burrowed to the surface, where they fed in a well-
18 U.S. NATIONAL MUSEUM BULLETIN 2 79defined vertical burrow. The first stadium averaged about 7 days.Second stage larvae resumed feeding very soon after moulting. Theyfed actively throughout the second stadium which averaged about 7to 8 days. The moults from first to second and from second to thirdstage larvae evidently took place in the burrow proper since no specialcells were found. The third stage larvae also resumed feeding verysoon after moulting; however, after about 7 to 8 days they ceasedfeeding and usually burrowed slightly deeper into the soil, where theyconstructed a smooth-walled pupal cell. The larvae either voided thecontents of their digestive tracts just prior to construction of the pupalcell or during construction, using the voided material to help firm upthe walls of the cell. Shortly after construction of the pupal cell thethird stage larvae entered the inactive prepupal stage. This stage hada duration of about 7 days, with the only movement being a wrigglingof the prepupae, especially when disturbed. During this period theprepupae underwent a shortening and a thickening. The pupal stagehad a duration of about 8 to 9 days. The moult from pupa to adultalways occurred while the pupa rested on its venter. After ecdysis theadults remained quiescent for several days before leaving the pupal cell.During this quiescent period the adults underwent the normalhardening and darkening processes.Total time from egg to adult in the laboratory varied from about 44to 50 days. The larvae hatching from the first clutches of eggs appearedto have greater vitality and to develop more rapidly than those hatch-ing from eggs oviposited late in the reproductive cycle of the female.One adult T. scaler, one first instar larva, and 1 1 third instar larvaewere collected by J. F. Cornell from a Berlese sample collected June27, 1966, about 14 miles south of Corvallis, Oreg. The sample consistedof the nest material of a wood rat {Neotoma sp.) and the duff and severalinches of soil from beneath the nest. The stage of development and sizeof the larvae compared quite well with the laboratory-derived lifehistory data.A single female of T. fascifer LeConte was collected May 18, 1963, atblack light in Corvallis, Oreg., by the writer. A total of 60 eggs andlarvae was retrieved from the container housing this specimen. Thisspecies also was observed to oviposit at a depth of about 1 to 3 mm. Itceased ovipositing by July 17, 1963. The total time required for thedevelopment of the larvae cloosely approximated that for T. scaler.The recorded time for the pupal stage was longer, averaging 1 1 days.The females of the genus Omorgus were observed to enter the soilto a depth of about 4 to 10 inches in order to oviposit. They usuallydeposited a clutch of four eggs, less commonly three eggs. The larvaehatched after about 8 days and pupated about 22 days later. Theaverage duration of the pupal stage for three species (0. monachus,0. carinatus, 0. asper) was 14 to 15 days at room temperature.
LARVAL TAXONOMY OF THE TROGINAE IN NORTH AMERICA 19The above life history data are similar to those of Leefmans (1932).According to his data, eggs of T. costatus Wied. required about 8days before hatching occurred. The larvae pupated about 31 to 42days later. The pupal stage had a duration of about 11 to 12 days,and the adult quiescent period varied from 10 to 13 days.
Keys to the Known Third (Final) Stage LarvaeThe keys presented below separate the final or third stage lar\'ae of14 species and four groups of two and three species each. The fourspecies groups have the following compositions: scaber and fascifer;spinulosus dentibius and foveicollis; plicatus, robinsoni, and tuberculatus; asper,punctatus, and carinatus. The known ranges of certain of the species inthe above groups are mutually exclusive, at least in part. The larvaecould be tentatively identified, therefore, on this basis. See Vaurie(1955), Howden and Vaurie (1957) and Vaurie (1958) for the knownranges of the species of Trox and Omorgus in North America.
KEY TO THE GENERA
Spiracles biforous (fig. 56). Antenna with distal sensory cone onsegment 2 (fig. 20). Maxillar/ stridulatory area with curveddouble row or patch of stridulatory teeth (figs. 41 and 42). TroxSpiracles cribriform (fig. 59). Antenna without sensory cone, withslightly concave distal sensory area on segment 2 (fig. 21).Maxillary stridulatory area with single straight row of stridu-latory teeth (fig. 49) Omorgus
KEY TO THE KNOWN THIRD STAGE LARVAE OF TROX
1
.
Epipharynx with 4 smaller sensory spots distad of 2 larger, setiferoussensory spots on haptomicrum (figs. 3, 6, and 8). \Vith only 2sensory spots on pedium distad of slightly arching, transverse rowof sensory spots (figs. 3, 6, and 8) 2Epipharynx with 2 smaller sensory spots distad of 2 larger, setiferoussensory spots on haptomerum (figs. 2, 4, 5, and 7). With 4 sensoryspots on pedium distad of slightly arching, transverse row ofsensory spots (figs. 2, 4, 5, and 7) 42. Dorsal lobe 1 (DLl) of abdominal segments 1 to 4 with transverse,irregular double row of about 25 to 40 spinules (fig. 37). Withprominent median epicranial setae (fig. 1) atrox
20 U.S. NATIONAL MUSEUM BULLETIN 27 9Dorsal lobe 1 (DLl) of abdominal segments 1 to 4 with singletransverse row of about 10 to 14 spinules (fig. 36). Medianepicranial setae very small or absent 33. Median group of phobae on pedium usually restricted to rightside (fig. 6). Frons broadly rounded posteriorly and very promi-nendy pitted (fig. 54) aequalisMedian group of phobae on pedium not restricted to right side(figs. 3 and 8). Frons more abruptly narrowed posteriorly andless prominently pitted (figs. 55 and 58) . . scaber and fascifer4. Dorsal lobe 1 (DLl) of abdominal segments 1 to 4 with singletransverse row of about 12 to 20 spinules (fig. 36) 5Dorsal lobe 1 (DLl) of abdominal segments 1 to 4 with transverse,irregular double row or transverse band of about 20 to 50 spinules(fig. 37) ? ? ? ^5. Head capsule width usually greater than 1.90 mxn. With 1 longsensory seta and 5 sensory pegs at distal end of segment 3 ofantenna (figs. 45 and 46) variolatusHead capsule width less than 1 .90 mm. With 6 sensory pegs at endof segment 3 of antenna, lack long sensory seta (figs. 44 and47) spinulosus dentibius and foveicollis6. Cranium light orange to light yellow brown. With 6 sensory pegsat end of segment 3 of antenna, lacks long sensory seta (fig.44) fronteraCranium red brown to black. With long sensory seta and 5 sensorypegs at end of segment 3 of antenna (fig. 45) 77. Head capsule red brown; width usually less than 2.30 mm. Laterallobe 3 of abdoiiainal segments 7 and 8 without setae . . sordidusHead capsule red brown to black; width usually greater than2.35 mm. Lateral lobe 3 of abdominal segments 7 and 8 with atleast 1 seta each (fig. 22) 88. Lateral margins of epipharynx with pronounced asperites (fig. 7).Epipharynx with at least 4 setae on each side caudolaterad ofsensory area of haptomerum (fig. 7) unistriatusLateral margins of epipharynx without asperites near base (fig. 4).Epipharynx usually with 3 or fewer setae on each side caudo-laterad of sensory area of haptomerum (fig. 4) 99. Postclypeus usually with 3 long setae on each side. With 20 ormore setae on lateral lobe of mesothorax. With 5 or more setaeon lateral lobe 2 of abdominal segment 9 (fig. 22) . . sonoraePostclypeus with 2 or 3 setae on each side, if 3, then third is alwaysmuch smaller than other two setae. With less than 20 setae onlateral lobe of mesothorax. Usually with 4 or fewer setae onposterior lateral lobe of abdominal segment 9.plicatus, robinsoni, and tuberculatus
LARVAL TAXONOMY OF THE TROGINAE IN NORTH AMERICA 21KEY TO THE KNOWN THIRD STAGE LARVAE OF OMORGUS
1. Dorsal lobe 1 of first 4 abdominal segments with transverse rowof spinules only, very rarely with 1 long seta per segment (fig.33) 2Dorsal lobe 1 of first 4 abdominal segments with at least 6 setae inaddition to transverse row of spinules 32. Frons with posterior frontal setae (fig. 24) monachusFrons without posterior frontal setae fuliginosus3. Cranium with large concavity on median border of eyespot. Con-cavity with single seta. Concavity about same size as eyespot;anterior border declivous; posterior border vertical (fig. 25) . 4Cranium smooth mediad of eyespot, or with at most a very shallowdepression with a single seta 54. Galea with at least 4 setae on dorsal surface in addition to whorl of5 setae at base of terminal uncus (fig. 49) texanusGalea without setae on dorsal surface, only with whorl of 5 setaeat base of terminal uncus (fig. 26) rubricans5. Epipharynx with group of phobae mediad of right fused phobalmass (fig. 11) suberosusEpipharynx without group of phobae mediad of right fused phobalmass (fig. 9) 66. Lacinia with 1 or more exterior setae (fig. 26) injlatusLacinia without exterior setae 77. Head capsule width greater than 5.0 mm. Each tibiotarsus withaverage of 2 1 to 26 setae. Epipharynx as in figure 1 1 . scutellarisHead capsule width less than 4.5 mm. Each tibiotarsus withaverage of 15 to 21 setae .... punctatus, asper, and carinatus
Generic Description of Trox Larvae
Larvae of this genus may be characterized as follows: Cranium(fig. 1) light orange or light orange brown, red brown, or dark redbrown to black. Cranium usually slightly reticulate posterior to posteriorfrontal setae, with prominent elevated and depressed areas anteriorto posterior frontal setae. Cranium strongly pitted in T. fascifer, T.aequalis, and T. scaber; pits very small or lacking in other species.With 1 dorsal epicranial seta and 1 median epicranial seta on eachside (median epicranial seta very short or absent in above threespecies). With about 5 to 12 long setae near each antenna and withsmall, slightly raised, nonpigmented eyespot at base of each antenna.Frons with paired posterior, median, exterior, and anterior setae.Each anterior angle of frons with 1 seta. Frontoclypeal suture indistinct.
22 U.S. NATIONAL MUSEUM BULLETIN 2 79
especially in median i-egion. Postclypeus as dark oi' darker thancranium, with 2 or 3 setae on each side. Preclypeus light yellow,glabrous. Labrum (fig. 1) symmetrical, darker than preclypeus, withpaired median, lateral, anterolateral, and anterior setae. Lateralmargins evenly rounded to sharply angulate; anterior margin broadlyrounded to weakly bilobed or trilobed. Antennae (figs. 1 and 20)three-segmented, terminal segment much reduced. Segment 2 withprominent, distal sensory cone. Segment 3 with terminal sensory pegs;all groups except terrestris group with 5 pegs and 1 seta (figs. 45 and 46)
;
terrestris group with 6 pegs (figs. 44 and 47). Epipharynx (figs. 2 and3-8) with about 4 to 1 3 stout setae on each side of corypha. Clithrapresent. Corypha with 4 prominent setae arising from marginal tu-bercles. Haptomerum at least partially sclerotized, with central,elevated, lightly sclerotized sensory area usually with 2 (4 in scalergroup) smaller sensory spots distad of 2 larger, setiferous sensory spots.Haptomerum also with about 1 to 6 setae posterolaterad of sensoryarea on each side. Setae often overlapping paria. Anterior border ofpedium usually with 4 (2 in scaler group) sensory spots distad of slightlyarching, transverse row of about 10 to 16 sensory spots. Pedium usuallywith curving, continuous row of inwardly directed phobae near lateraland anterior borders, anterior phobae proximad of sensory spots usuallyvery small; or pedium with slightly oblique row of inwardly directedphobae along lateral border on each side, these rows usually joinedanteriorly by transverse row of reduced phobae proximad of sensoryspots. Variations of the above 2 basic patterns also occur. Pedium withadditional pronounced median, transverse patch of caudally directedphobae. With a fused phobal mass on each side of pedium near poste-rior border. Pedium often with smaller phobae mediad or proximadof fused phobal masses, latter phobae usually more pronounced onright side when present. Paria with posterior group of about 5 to 13stout setae on each side near tormae. Tormae symmetrical; unitedmedially, with anterior epitorma and prominent pternotormae.Haptolachus with 2 elevated, sclerotized plates flanking median, non-pigmented, elevated area. Sclerotized plates unequal, left plate smaller.Median elevated area with numerous phobae in area between sclerotizedplates; usually with 4 sensory spots posteriorly. Haptolachus also with2 macrosensilla in membranous areas on each side of central elevatedarea. Glossa (fig. 19) with 4 sensory spots and usually 4 to 6 setaedorsally; with 2 sensory spots and 2 long setae ventrally. Labial palpitwo-segmented; basal segment with terminal, exterior phobal fringe,Hypopharynx (fig. 19) divided into smaller distal area and largerproximal area. Distal area with 2 sensory spots distad of transverse rowof about 10 to 18 sensory spots. Lateral regions of smaller distal areaeach with slightly oblique row of phobae. Larger proximal area withsymmetrical subtormae adjoining medially and bearing paired sub-
LARVAL TAXONOMY OF THE TROGINAE IN NORTH AJMERICA 23
apotormae. Central, depressed area bordered laterally and posteriorlyby row of inwardly directed, closely set phobae. Distal phobae on rightside usually curving slightly mediad to connect with patch of phobaenear apex of right subapotorma. Hypopharynx also with prominent,elevated, sclerotized process located above point where subtormaeadjoin. Maxilla (figs. 41 and 42) with galea and lacinia separate.Lacinia with 3 prominent unci and about 10 to 22 marginal setae.Two-segmented galea with whorl of 5 setae at base of terminal uncus.Four-segmented maxillary palpus with 1 seta on basal segment and2 setae on segment 3. Stipes and cardo each with 1 seta on exteriorsurface. Maxillary stridulatory area with curved double row or curvedpatch of small stridulatory teeth.Mandibles (figs. 40 and 43) darker than head capsule, with 2widely spaced setae in dorsal exterior groove. Left mandible slightlylonger. With small, sharp tooth (S3) proximad of scissorial notchof left mandible. With larger, rounded tooth (S2) proximad of scis-sorial notch of right mandible. Both mandibles with single tooth(S4 of left mandible and S3 of right mandible) on inner margin be-tween scissorial and manducatorial areas. Tooth on left m.andibleusually larger. With small brustia near base of tooth on ventral surfaceof each mandible. Molar area of left mandible hollowed to receiveright mandible. Each mandible with brustia on median border nearbase.Prothorax (fig. 39) with prominent yellow brown to dark brown,sclerotized shield on each side; shield bordered with setae. Setaemore numerous on anterior border and not continuous across dorsalnonsclerotized area between shields. With 2 lateral lobes with about1 to 10 setae each. Biforous spiracle located caudodorsad posteriorof 2 lateral lobes. Sternum with or without a few small setae.Mesothorax (fig. 39) divided dorsally into larger anterior lobe(DLl) and smaller posterior lobe (DL2). DLl with transverse row ofabout 14 to 40 setae. DL2 without setae. Lateral lobe with about 2to 30 setae. Sternum usually with gi'oup of about 2 to 8 setae on eachof 2 lobes.Metathorax also divided dorsally into larger anterior lobe (DLl)and smaller posterior lobe (DL2). DLl with transverse row of about15 to 45 setae and 2 spinules. Spinules widely separated and anteriorto row of setae. DL2 often with 1 or 2 spinules. With 2 lateral lobes;anterior lobe usually very small and with to about 4 setae, largerposterior lobe with about 3 to 10 setae. Sternum with about 2 to 10setae on each of 2 lobes.Infraepisternal area usually with 1 large seta on prothorax, with orwithout large setae on mesothorax, usually without large setae onmetathorax. Infraepimeral area usually with 2 to 10 large setae, setaeusually increasing in number from prothorax to metathorax.
24 U.S. NATIONAL MUSEUM BULLETIN 279Legs (fig. 38) four-segmented and subequal, becoming slightlylonger posteriorly. Short setae numerous on all 4 segments; longsetae only on 2 basal segments. Each leg with long, terminal clawwith 2 setae. Tibiotarsus with 2 whorls of 6 setae each.Abdomen (dorsal aspect, figs. 35, 36, and 37) with segments 1 through8 with 3 dorsal lobes (DLl, DL2, and DL3) and lateral biforousspiracles. Segments 1 through 4 with similar setal pattern. Setae usuallyincreasing in number from segment 1 to about segment 3. Withtransverse row or band of only spinules on DLl and DL3. With trans-verse row or band of spinules plus setae on DL2. Setae usually posteriorto spinules, becoming more numerous laterally and often intergradingwith setae of spiracular lobe. DL3 with 2 associated dorsolateral lobes(DL3a and DL3b) usually with a few scattered setae or spinules.Segments 5 and 6 with setal pattern similar to segments 1 to 4 withexception of DL3. DL3 with narrow, transverse patch of spinulesflanked anterolaterally by small group of spinules on DL3b. DL3ausually with a few small setae. DL3a and DL3b greatly reduced on allsegments posterior to segment 6. Segment 7 with transverse group ofspinules or setae on DLl. DL2 with transverse row or band of setae orof intermixed setae and spinules. DL3 glabrous, with transverse rowof about 1 to 15 small setae, or with isolated, small spinules. Segment 8with transverse row of about 4 to 10 setae on DLl. DL2 with transverserow of about 6 to 20 setae. DL3 glabrous or with up to about 7 scattered,small setae. Segment 9 with 2 rows of setae ; anterior row with about4 to 8 long setae, posterior row with about 4 to 10 long and short setae.Segment 10 with 1 or 2 rows of caudally directed spiniform setae.Abdomen (lateral aspect, fig. 35) with segments 1 through 8 with3 setae-bearing lobes (LLl, LL2, and LL3). LLl with about 1 to 4setae ; LL2 with about 2 to 8 setae ; LL3 with to about 4 setae. Setaeon each respective lobe usually decreasing in number posteriorly fromabout segment 3 to segment 8. Segment 9 with only 2 lateral lobes.LLl with about 1 to 3 setae; larger posterior lobe (LL2) with about 3to 10 setae. Segment 10 usually with 2 rows of caudally directedspiniform setae; anterior row of setae usually reduced in size andnumber.Abdomen (ventral aspect, similar to fig. 28) with 3 transverse lobes(VLl, VL2, and VL3). VLl without setae. VL2 with transverse rowof about 8 to 24 setae on segments 1 and 2, decreasing to about 2 to 10setae on segment 9. VL3 constricted in median region, expandedlaterally, with about 4 to 10 setae on each side on anterior segments,decreasing to about 1 to 3 setae on each side on segment 9. Numberand size of setae and size of lobes on venter usually decreasing pro-gressively from about segment 3 to segment 9. Segment 10 with 2 rowsof caudally directed spiniform setae, anterior row reduced in size and
LARVAL TAXONOMY OF THE TROGINAE IN NORTH AMERICA 25
number. Both rows narrowly discontinuous in median region. Analopening surrounded by single dorsal lobe and 2 larger ventral lobes(fig. 53).
Species Descriptions of Trox Larvae
Troxfascijer LeConte
Troxjascifcr LeConte, 1854, Proc. Acad. Nat. Sci. Philadelphia, vol. 7, p. 213.Description based upon the following material. Twenty-eightlarvae reared from a single female taken in a black light trap inCorvallis, Benton Co., Oreg., May 18, 1963, by Charles W. Baker.LI: head capsule width 0.89 to 0.93 mm.; 2 specimens.LII: head capsule width 1.20 to 1.24 mm.; 2 specimens.LIII: head capsule width 1.64 to 1.86 mm.; 24 specimens.
Description of Third Stage LarvaFigures 8 and 55Cranium light orange to light orange brown, with numerous promi-nent pits. Median epicranial setae very small or absent. Exterior andanterior setae of frons very small. Postclypeus with 1 long and 1 shortseta on each side. Epipharynx with about 5 to 6 marginal setae oneach side of corypha. Sensory area of haptomerum with 4 smallersensory spots distad of 2 larger setiferous sensory spots. Haptomerumalso with 1 large seta on each side of sensory area, seta on right sideusually only slightly removed from anterior border; distad of seta onleft side. Anterior region of pedium usually with 2 sensory spots distadof transverse, slightly arching row of about 10 sensory spots. Tormacwith short, stout pternotormae. Hypopharynx with smaller distalarea with 2 sensory spots distad of transverse row of about 10 sensoryspots. Maxilla with lacinia with 3 prominent unci and about 10 to 12marginal setae.Prothorax with about 2 setae on anterior lateral lobe, usually withabout 4 setae on posterior lateral lobe. Infraepisternal region usuallywith 1 seta; infraepimeral area usually with 2 setae.Mesothorax with about 4 setae on lateral lobe. Infraepisternalarea usually without setae; infraepimeral area with about 2 setae.Metathorax with or without single seta on anterior lateral lobe.Posterior lateral lobe wdth about 5 setae. Infraepisternal region usuallywithout setae ; infraepimeral area with about 2 setae.
26 U.S. NATIONAL MUSEUM BULLETIN 279Abdomen (dorsal aspect) with DLl of segments 1 through 4 withsingle transverse row of about 14 spinules. DL3 with single row ofabout 4 to 8 spinules. Segment 7 with transverse row of about 12 to14 intermixed setae and spinules on DLl. DL2 with transverse row ofabout 18 to 20 long and short setae. DL3 with a few scattered smallsetae.Abdomen (lateral aspect) with segments 1 to 8 usually with 1 to2 setae on LLl ; LL2 usually with 2 to 4 setae; LL3 with about 1 or2 setae. Trox scaber (Linnaeus)Silpha scabra Linnaeus, 1767, Systema naturae, ed. 12, p. 573.Description based on the following material. Twenty-six larvaereared from a single female collected at black light about 10 milesnorth of Corvallis, Benton Co., Oreg., April 26, 1965, by Charles W.Baker. Twenty-two larvae reared from Fi adults of the above female.Four larvae collected from palm tubs in Bremen, Germany, June-July, 1930, by J. D. Alfken. Loaned by P. O. Ritcher.LI : head capsule width 0.80 to 0.93 mm. ; 1 1 specimens.LII: head capsule width 1.02 to 1.27 mm.; 17 specimens.LIII: head capsule width 1.39 to 1.70 mm.; 24 specimens.
Description of Third Stage LarvaFigures 3, 23, 40, 41, 46, and 58Cranium light orange to light orange brown; with numerous prom-inent pits. Median epicranial setae very short or absent. With about 5long setae near each antenna. Exterior and anterior setae of frons veryshort. Postclypeus usually with 1 long and 1 short seta on each side.Epipharynx with about 4 to 5 marginal setae on each side of corypha.Sensory area of haptomerum usually with 4 smaller sensory spotsdistad of 2 larger setiferous sensory spots. Haptomerum also with 1large seta on each side of sensory area, seta on right side usually onlyslightly removed from anterior border of epipharynx. Anterior regionof pedium usually with 2 sensory spots distad of slighdy arching,transverse row of about 10 sensory spots. Hypopharynx with distalarea with 2 sensory spots distad of transverse row of about 10 sensoryspots. Maxilla with lacinia bearing 3 unci and about 10 to 12 stoutsetae.Prothorax with about 1 or 2 setae on anterior lateral lobe, usuallywith 1 seta on posterior lateral lobe. Infraepisternal and infraepimeralareas usually with 1 seta each.Mesothorax with about 3 setae on lateral lobe. Infraepisternal areausually without setae; infraepimeral area usually with 1 seta.
LARVAL TAXONOMY OF THE TROGINAE IN NORTH AMERICA 27Metathorax usually without setae on anterior lateral lobe, withabout 3 to 5 setae on posterior lateral lobe. Infraepisternal area usuallywithout setae; infraepimcral area usually with 1 seta.Abdomen (dorsal aspect) with DLl of segments 1 through 4 withsingle transverse row of about 10 to 14 spinules, DL3 with transverserow of about 4 to 8 spinules. Segment 7 with transverse row of about10 to 12 spinules on DLl. DL2 with diffuse transverse row of spiniformsetae and setae. DL3 with or without a few very small spiniform setae.Abdomen (lateral aspect) with segments 1 to 8 usually with 1 setaon LLl ; LL2 with about 3 setae; LL3 usually with 1 seta.Trox aequalis SayTrox aequalis Say, 1831, New species of . . . insects found . . . chiefly inLouisiana, p. 5.Description based on the following material. Fifteen larvae with3 associated adults collected in a buzzard's nest on Jackson's Island,Md., July 13, 1912, by Carnochan and Barber. Nineteen larvaewith 1 associated adult collected in a buzzard's nest on Jackson'sIsland, Md., June, 1919, by Carnochan and Barber.Loaned by U.S. National Museum,LI : head capsule width 0.86 to 0.90 mm. ; 2 specimens.LI I: head capsule width 1.17 to 1.31 mm.; 12 specimens.LIII: head capsule width 1.64 to 1.86 mm.; 20 specimens.
Description of Third Stage LarvaFigures 6 and 54Cranium light orange to light orange brown, with numerous prom-inent pits. Median epicranial setae usually absent. With about 5 longsetae near base of each antenna. Exterior and anterior setae on fronsvery short. Postclypeus usually with 1 long seta and 1 short seta oneach side. Epipharynx usually with 4 marginal setae on each sideof corypha. Sensory area of haptomerum usually with 4 smallersensory spots distad of 2 larger, setiferous sensory spots. Haptomerumalso usually with 1 seta on each side anterolaterad of sensory area,seta on right side being only slightly removed from anterior border ofepipharynx. Anterior region of pedium usually with 2 sensory spotsdistad of slightly arching, transverse row of about 10 sensory spots.Hypopharynx with distal area with 2 sensory spots distad of trans-verse row of about 10 sensory spots. Maxilla with lacinia with 3 unciand about 10 marginal setae.Prothorax usually with 1 seta on anterior and posterior lateral lobes.Infraepisternal and infraepimcral areas usually with 1 seta each.2S5-935?68 3
28 U.S. NATIONAL MUSEUM BULLETIN 2 79Mesothorax with about 3 or 4 setae on lateral lobe. Infraepisternalarea usually without long setae; infraepimeral area usually with 1 seta.Metathorax with or without 1 seta on anterior lateral lobe andabout 2 or 3 setae on posterior lateral lobe. Infraepisternal area usuallywithout long setae; infraepimeral area usually with 1 or 2 setae.Abdomen (dorsal aspect) with DLl of segments 1 to 4 with trans-verse row of about 8 to 12 spinules, DL3 with transverse row of about2 to 6 spinules. Segment 7 with transverse row of about 6 to 1 spiniformsetae on DLl, DL2 with transverse row of short and long setae. DL3with or without a few very small setae.Abdomen (lateral aspect) with segments 1 to 8 usually with 1 setaon LLl; LL2 usually with 2 setae; LL3 usually with 1 seta.
Trox atrox LeConteTrox atrox LeConte, 1854, Proc. Acad. Nat. Sci. Philadelphia, vol. 7, p. 214.Description based on the following material. Thirty larvae rearedfrom 6 adults collected at black light about 2.5 miles east of Hermiston,Umatilla Co., Oreg., June 11-13, 1963, by Charles W. Baker. Tenlarvae reared from 4 adults collected under chicken remains and adead crow about 5.0 miles west of Tularosa, Otero Co., N. Mex.,July 22, 1964, by David R. Smith and Charles W. Baker. Sevenlarvae reared from 1 adult collected under chicken remains about4.0 miles north of Las Cruces, Dona Ana Co., N. Mex., July 22, 1964,by David R. Smith and Charles W. Baker.LI : head capsule width 1 .05 to 1.15 mm. ; 9 specimens.LII: head capsule width 1.39 to 1.58 mm.; 6 specimens.LIII: head capsule width 1.98 to 2.39 mm.; 32 specimens.
Description of Third Stage LarvaFigures 23 and 38Cranium yellow orange to light yellow brown, with about 10 to 14setae near each antenna. Postclypeus with 3 setae on each side.Epipharynx with about 8 to 10 marginal setae on each side of corypha.Sensory area of haptomerum usually with 4 smaller sensory spotsdistad of 2 larger setiferous sensory spots. Haptomerum also with1 seta on left side anterolaterad of sensory area. Anterior region ofpedium with 2 sensory spots distad of slighdy arching transverse rowof about 12 to 14 sensory spots. Tormae with short, stout pternotorinae.Hypopharynx with smaller distal area with 2 sensory spots distad oftransverse row of about 1 2 sensory spots. Maxilla with lacinia with 3unci and about 12 to 15 stout marginal setae.
LARVAL TAXONOMY OF THE TROGINAE IN NORTH AMERICA 29Prothorax with about 4 setae on anterior lateral lobe and about 8setae on posterior lateral lobe. Infraepisternal area usually with 1seta; infraepimeral area with about 3 setae.Mesothorax with about 10 setae on lateral lobe. Infraepisternal areausually without setae ; infraepimeral area with about 8 setae.Metathorax with about 2 setae on anterior lateral lobe, with about10 setae on posterior lateral lobe. Infraepisternal area usually withoutsetae; infraepimeral area with about 8 setae.Abdomen (dorsal aspect) with DLl of segments 1 through 4 withtransverse band of about 25 to 40 spinules. DL3 with transverse row ofabout 8 to 14 spinules. Segment 7 with transverse group of about 30short setae plus scattered spinules on DLl. DL2 with transverse bandof setae. DL3 with scattered setae.Abdomen (lateral aspect) with segments 1 to 8 with about 2 to 3setae on LLl ; LL2 with about 4 to 8 setae; LL3 with about 2 to 4 setae.
Trox spinulosus dentihius RobinsoaTrox (Trox) dentibius Robinson, 1940, Trans. Amer. Ent. See, vol. 66, p. 156,pi. 4, figs. 4, 14.Trox spinulosus dentibius Robinson, Vaurie, 1955, Bull. Amer. Mus. Nat. Hist.,vol. 106, p. 38, figs. 6, 251.Description based on the following material. Twenty-eight larvaereared from adults collected at black light at the Southwest ResearchStation, Cochise Co., Ariz., July 4-8, 1963, by Noel McFarland. Sixlarvae reared from adults collected under a coyote carcass about 3.0miles east of La Liaz, Otero Co., N. Mex., July 22, 1964, by David R.Smith and Charles W. Baker.LI: head capsule width 0.99 to 1.03 mm.; 3 specimens.LII: head capsule width 1.27 to 1.40 mm.; 10 specimens.LIII: head capsule width 1.55 to 1.86 mm.; 21 specimens.
Description of Third Stage LarvaFigures 5 and 47Cranium orange brown to light red brown, with about 6 long setaenear each antenna. Anterior setae of frons reduced. Postclypeus with2 or 3 setae on each side, if 3, then third is very short. Epipharynxwith about 5 marginal setae on each side of corypha. Sensory area ofhaptomerum with 2 smaller sensory spots distad of 2 larger, setiferoussensory spots. Haptomerum also usually with 2 setae on each sidecaudolatcrad of sensory area. Anterior region of pedium usually with4 sensory spots distad of slightly arching transverse row of about 10sensory spots. Hypopharynx with smaller distal area with 2 sensory
30 U.S. NATIONAL MUSEUM BULLETIN 2 79
spots distad of transverse row of about 10 sensory spots. Maxilla withlacinia with 3 unci and about 12 stout marginal setae.Prothorax usually with 1 seta on anterior lateral lobe and 1 or 2setae on posterior lateral lobe. Infraepisternal area usually with 1seta; infraepimeral area usually with 1 or 2 setae.Mesothorax with about 4 to 6 setae on lateral lobe. Infraepisternalarea usually without setae ; infraepimeral area usually with 2 setae.Metathorax usually without setae on anterior lateral lobe, with about4 to 5 setae on posterior lateral lobe. Infraepisternal area usuallywithout setae; infraepimeral area with about 2 to 3 setae.Abdomen (dorsal aspect) with DLl of segments 1 through 4 withsingle transverse row of about 14 to 20 spinules, DL3 with singletransverse row of about 4 to 10 spinules. Segment 7 with transverserow of about 10 to 14 spinules on DLl. DL2 with scattered spinulesintermixed in transverse row of setae. DL3 with scattered setae.Abdomen (lateral aspect) with segments 1 through 8 usually with1 seta on LLl ; LL2 usually with 3 setae; LL3 usually with 2 setae.
Trox foveicollis HaroldTrox foveicollis Harold, 1872, Coleopterologische Hefte, vol. 9, page 181.Description based on the following material. Thirty-six larvaereared from adults collected under chicken remains about 4 milesnorth of Bronson, Sabine Co., Tex., July 7, 1964, by David R. Smithand Charles W. Baker.LI : head capsule width 0.93 to 0.96 mm. ; 9 specimens.LII: head capsule width 1.20 to 1.30 mm.; 7 specimens.LIII: head capsule width 1.61 to 1.74 mm.; 20 specimens.
Description of Third Stage LarvaFigure 36Cranium orange brown to light red brown, with about 6 long setaenear each antenna. Anterior setae of frons somewhat shorter. Post-clypeus usually with 2 setae on each side. Epipharynx with about5 to 6 marginal setae on each side of corypha. Sensory area of hapto-merum with 2 smaller sensory spots distad of 2 larger setiferous sensoryspots. Haptomerum also usually with 2 setae caudolaterad of sensoryarea. Anterior region of pedium usually with group of 4 sensoryspots distad of slightly arching transverse row of about 10 sensoryspots. Hypopharynx with smaller distal area usually with 2 sensoryspots distad of transverse row of about 10 sensory spots. Maxilla withlacinia with 3 unci and about 10 to 11 stout marginal setae.
LARVAL TAXONOMY OF THE TROGINAE IN NORTH AMERICA 31Prothorax usually with 1 or 2 setae on anterior and posterior laterallobes. Infraepisternal and infraepinieral areas usually with 1 seta each.Mesothorax with about 3 to 6 setae on lateral lobe. Infraepisternalarea usually without setae; infraepimeral area usually with 2 setae.Metathorax usually without setae on anterior lateral lobe, with about4 to 6 setae on posterior lateral lobe. Infraepisternal area usuallywithout setae; infraepimeral area usually with 2 setae.Abdomen (dorsal aspect) with DLl of segments 1 through 4 withsingle transverse row of about 12 to 18 spinules, DL3 with transverserow of about 6 to 10 spinules. Segment 7 with transverse row of about10 to 16 spinules on DLl. DL2 usually with 2 spinules intermixed intransverse row of setae. DL3 with or without a few scattered, smallsetae.Abdomen (lateral aspect) with segments 1 to 8 usually with 1 seta onLLl ; LL2 usually with 2 or 3 setae; LL3 usually with 1 or 2 setae.
Troxfrontera VaurieTroxJrontera Vaurie, 1955, Bull. Amer, Mus. Nat. Hist., vol. 106, p. 41, figs. 9,10, 25M.Description based on the following material. Thirty-eight larvaereared from 64 adults collected in soil under what was probably a veryold sheep or goat carcass about 0.5 miles east of Hebbronville, JimHogg Co., Tex., July 14-15, 1964, by David R. Smith and Charles W.Baker.LI : head capsule width 1.11 to 1.21 mm. ; 7 specimens.LII: head capsule width 1.48 to 1.62 mm.; 13 specimens.LIII: head capsule width 1.95 to 2.21 mm.; 18 specimens.
Description of Third Stage LarvaFigures 16, 17, 18, and 44Cranium light orange to light yellow brown, with about 6 to 9 setaenear each antenna. Postclypeus with 3 setae on each side. Epipharynxwith about 7 to 10 marginal setae on each side of corypha. Sensoryarea of haptomerum usually with 2 smaller sensory spots distad of 2larger, setiferous sensory spots. Haptomerum usually also with 2 setaeon each side caudolaterad of sensory area. Anterior region of pediumusually with 4 sensory spots distad of slightly arching row of about 10to 12 sensory spots. Hypopharynx with smaller distal area with 2sensory spots distad of transverse row of about 11 to 13 sensory spots.Maxilla with lacinia with 3 unci and about 12 to 15 stout marginalsetae.
32 U.S. NATIONAL MUSEUM BULLETIN 2 79Prothorax usually with 2 setae on anterior lateral lobe and about8 setae on posterior lateral lobe. Infraepisternal area usually with 1seta; infraepimeral area with about 4 setae.Mesothorax with about 11 setae on lateral lobe. Infraepisternalarea usually without setae; infraepimeral area with about 6 setae.Metathorax with about 2 setae on anterior lateral lobe and about1 1 setae on posterior lateral lobe. Infraepisternal area usually withoutsetae; infraepimeral area with about 6 setae.Abdomen (dorsal aspect) with DLl of segments 1 through 4 withtransverse band of about 24 to 28 spinules, DL3 with single transverserow of about 11 to 19 spinules. Segment 7 with transverse band ofabout 6 to 12 spinules and about 17 small setae on DLl. DL2 withtransverse row of numerous setae. DL3 with transverse row of about10 to 14 small setae.Abdomen (lateral aspect) with segments 1 to 8 usually with 1 to 2setae on LLl ; LL2 with about 3 to 7 setae; LL3 with about 2 to 4 setae.
Trox robinsoni VaurieTrox robinsoni Vaurie, 1955, Bull. Amer. Mus. Nat. Hist., vol. 106, p. 47,figs. 12, 13, 25P.Description based on the following material. Twenty-nine larvaereared from adults collected under a bird carcass near Kerrville, KerrCo., Tex., September 12-13, 1964, by Larry J. Bottimer.LI: head capsule width 1.45 to 1.55 mm.; 5 specimens.LII: head capsule width 1.86 to 2.00 mm.; 7 specimens.LIII: head capsule width 2.35 to 2.64 mm.; 16 specimens.
Description of Third Stage LarvaFigure 39Cranium deep red brown to brown, with about 4 to 8 long setaenear each antenna. Postclypeus usually with 2 or 3 setae on each side,if 3, then tliird is very short. Epipharynx with about 7 to 9 stout mar-ginal setae on each side of corypha. Sensory area of haptomerumusually with 2 smaller sensory spots distad of 2 larger, setiferous sensoryspots. Haptomerum also with 2 setae on each side caudolaterad ofsensory area. Anterior region of pedium usually with 4 sensory spotsdistad of slightly arching transverse row of about 12 to 14 sensory spots.Hypopharynx with smaller distal area usually with 2 sensory spotsdistad of transverse row of about 12 sensory spots. MaxiUa with laciniawith 3 unci and about 14 to 18 stout marginal setae.Prothorax usually with about 1 to 2 setae on anterior lateral lobeand usually with 1 seta on posterior lateral lobe. Infraepisternal andinfraepimeral areas usually with I long seta each.
LARVAL TAXONOMY OF THE TROGINAE IN NORTH AMERICA 33Mesothorax with about 1 3 to 1 7 setae on lateral lobe. Infraepisternalarea with to about 3 very small setae; infraepimeral area withabout 3 to 5 long setae.Metathorax usually without setae on anterior lateral lobe, sometimeswith 1 seta. With about 5 to 7 setae on posterior lateral lobe. Infra-episternal area with about 1 to 3 very small setae, infraepimeral areawith about 2 to 4 long setae.Abdomen (dorsal aspect) with DLl of segments 1 through 4 withtransverse band of about 20 to 31 spinules, DL3 with transverse rowof about 6 to 12 spinules. Segment 7 with transverse band of about 24to 32 spinules on DLl. DL2 with about 4 to 5 scattered, small spinulesplus row of setae. DL3 with about 2 to 5 small setae.Abdomen (lateral aspect) with segments 1 to 8 usually with 1 setaon LLl; with 2 to 5 setae on LL2; with 1 to 2 setae on LL3.Trox pUcatus RobinsonTrox {Trox) pHcatus Robinson, 1940, Trans. Amer. Ent. Soc, vol. 66, p. 153,pi. 4, fig. 10.Description based on the following material. Forty-seven larvaereared from adults collected at lights at the Southwest ResearchStation, Cochise Co., Ariz., July 4-8, 1963, by Noel McFarland. Tenlarvae collected under a fawn carcass about 3.0 miles northwest ofMcDonald Observatory, JefF Davis Co., Tex., June 27, 1964, byDavid R. Smith and Charles W. Baker.LI: head capsule width 1.27 to 1.40 mm.; 22 specimens.LII: head capsule width 1.73 to 1.93 mm.; 11 specimens.LIII: head capsule width 2.26 to 2.60 mm.; 24 specimens.
Description of Third Stage LarvaCranium red brown to dark brown, with about 6 to 8 long setaenear each antenna. Postclypeus with 2 or 3 setae on each side, if 3,then third very small. Epipharynx with about 6 to 8 stout marginalsetae on each side of corypha. Sensory area of haptomerum usuallywith 2 smaller sensory spots distad of 2 larger, setiferous sensory spots.Haptomerum also usually with 2 setae on each side caudolaterad ofsensory area. Anterior region of pedium usually with 4 sensory spotsdistad of slightly arching transverse row of about 12 to 14 sensoryspots. Hypopharynx with smaller distal area usually with 2 sensoryspots distad of transverse row of about 12 sensory spots. Maxilla withlacinia with 3 unci and about 14 to 16 marginal setae.Prothorax with about 1 to 3 setae on anterior lateral lobe and about1 to 2 setae on posterior lateral lobe. Infraepisternal area usually with1 seta; infraepimeral area usually with 2 setae.
34 U.S. NATIONAL MUSEUM BULLETIN 279Mesothorax with about 10 to 13 setae on lateral lobe. Infraepisternalarea usually without setae; infraepimeral area with about 3 to 5 setae.Metathorax usually Vv^ith or 1 seta on anterior lateral lobe andabout 7 to 1 1 setae on posterior lateral lobe. Infraepisternal areausually without setae; infraepimeral area with about 2 to 6 setae.Abdomen (dorsal aspect) with DLl of segments 1 through 4 withtransverse band of about 21 to 34 spinules; DL3 with transverse rowof about 6 to 1 1 spinules. Segment 7 with transverse band of about25 to 29 spinules or spinules and spiniform setae on DLl. DL2 withabout 2 to 4 small spinules plus transverse row of setae. DL3 withtransverse row of about 5 to 15 small setae.Abdomen (lateral aspect) with segments 1 to 8 usually with 1 to3 setae on LLl; LL2 with about 2 to 5 setae; LL3 with about 1 to3 setae. Trox tuberculatus (De Geer)Scarabaeus tuberculatus De Geer, 1774, Memoires pour servir a I'histoire desinsectes, vol. 4, p. 318, pi. 19, fig. 2.Trox tuberculatus (De Geer) Vaurie, 1955, Bull. Amer. Mus. Nat. Hist., vol. 106,p. 51.Description based on the following material. Twenty larvae rearedfrom an aggregation of 18 adults collected as follows: 14 adults collectedunder a crow carcass and a cow carcass at the Boyce ThompsonInstitute Forest Research Laboratory, Hardin Co., Tex., July 3-5,1964, by Robert I. Gara, David R. Smith, and Charles W. Baker;4 adults collected under chicken remains in a dumpsite about 4.0 milesnorth of Bronson, Sabine Co., Tex., July 7, 1964, by David R. Smithand Charles W. Baker.LI: head capsule width 1.45 to 1.58 mm.; 3 specimens.LII: head capsule width 1.82 to 1.98 mm.; 4 specimens.LIII: head capsule width 2.44 to 2.63 mm.; 13 specimens.
Description of Third Stage LarvaFigures 15 and 37Cranium red brown to dark red brown, with about 5 or 6 setae neareach antenna. Postclypeus usually with 2 setae on each side, if 3, thenthird is very short. Epipharynx with about 7 to 9 setae on each sideof corypha. Sensory area of haptomerum usually with 2 smaller sensoryspots distad of 2 larger, setiferous sensory spots. Haptomerum alsousually with 3 to 4 setae on each side caudolaterad of sensory area.Anterior region of pedium generally with 4 sensory spots distad ofslightly arching, transverse row of about 12 to 14 sensory spots. Hypo-pharynx with smaller distal area usually with 2 sensory spots distad
LARVAL TAXONOMY OF THE TROGINAE IN NORTH AMERICA 35
of transverse row of about 10 to 12 sensory spots. Maxilla with laciniawith 3 unci and about 16 to 18 stout marginal setae.Prothorax usually with 1 or 2 setae on anterior and posterior laterallobes, with 1 seta on infraepisternal and infraepimeral areas.Mesothorax with about 1 1 to 12 setae on lateral lobe. Infraepisternalarea usually without setae ; infraepimeral area with about 3 setae.Metathorax usually with to 1 seta on anterior lateral lobe and about5 to 6 setae on posterior lateral lobe. Infraepisternal area usuallywithout setae; infraepimeral area with about 3 setae.Abdomen (dorsal aspect) with DLl of segments 1 through 4 withtransverse band of abovit 24 to 32 spinules. DL3 with transverse rowof about 9 to 16 spinules. Segment 7 with transverse band of about 26to 40 spinules on DLl. DL2 with about 6 to 12 scattered spinules plustransverse row of setae. DL3 with about 2 to 5 scattered, small setae.Abdomen (lateral aspect) with segments 1 to 8 usually with about1 to 2 setae on LLl ; with about 3 to 6 setae on LL2; with about 1 to2 setae on LL3. Trox sonorae LeConteTrox sonorae LeConte, 1854, Proc. Acad. Nat. Sci. Philadelphia, vol. 7, p. 211.Description based on the following material. Forty-eight larvaereared from an aggregation of 40 adults collected as follows : 5 at a cowcarcass about 18 miles south of Rodeo, Hildago Co., N. Mex., July 18,1964, by Martin A. Mortenson and Mont A. Cazier; 6 at the same cowcarcass July 25, 1964, by David R. Smith and Charles W. Baker; 29at a cow carcass about 6 miles east of Portal, Cochise Co., Ariz., July 24-25, 1964, by David R. Smith and Charles W. Baker. Two larvaereared from 12 adults collected at a sheep carcass about 6 miles south-east of Sheffield, Pecos Co., Tex., July 17, 1964, by David R. Smith andCharles W. Baker.LI: head capsule width 1.55 to 1.65 mm.; 10 specimens.LII: head capsule width 2.01 to 2.21 mm.; 12 specimens.LIII: head capsule width 2.48 to 3.05 mm.; 28 specimens.
Description of Third Stage LarvaFigures 4, 20, 22, 23, 31, 35, 43, 45, 52, 53, and 56Cranium dark brown to black, with about 8 to 12 long setae neareach antenna. Postclypeus with 3 long setae on each side. Epipharynxwith about 10 to 13 stout marginal setae on each side. Sensory area ofhaptomerum usually with 2 smaller sensory spots distad of 2 larger,setiferous sensory spots. Haptomerum also usually with 3 setae on eachside caudolaterad of sensory area. Anterior region of pedium usuallywith 4 sensory spots distad of slightly arching transverse row of about
36 U.S. NATIONAL MUSEUIVI BULLETIN 2 7914 to 16 sensory spots. Hypopharynx with smaller distal area usuallywith 2 sensory spots distad of transverse row of about 12 to 14 sensoryspots. Maxilla with lacinia with 3 unci and about 17 to 22 marginalsetae.Prothorax with about 1 to 3 setae on anterior lateral lobe andabout 2 to 4 setae on posterior lateral lobe. Infraepisternal area usuallywith 1 seta; infraepimeral area usually with 2 setae.Mesothorax with about 25 to 30 setae on lateral lobe. Infraepisternalarea with about 2 to 4 small setae; infraepimeral area with about 5to 7 long setae.Metathorax usually with 2 to 4 setae on anterior lateral lobe andabout 5 to 10 setae on posterior lateral lobe. Infraepisternal areausually with about 2 to 4 small setae; infraepimeral area with about6 to 8 long setae.Abdomen (dorsal aspect) with DLl of segments 1 through 4 withtransverse band of about 25 to 50 spinules. DL3 with transverse rowof about 6 to 17 spinules. Segment 7 with transverse band of about34 to 43 spinules on DLl. DL2 with about 2 to 7 small spinules plustransverse row of setae. DL3 with about 2 to 7 scattered, small setae.Abdomen (lateral aspect) with segments 1 to 8 usually with about1 to 3 setae on LLl; with about 3 to 7 setae on LL2; with about 1to 3 setae on LL3.
Trox variolatus MelsheimerTrox variolatus Melsheimer, 1846, Proc. Acad. Nat. Sci. Philadelphia, vol. 2,p. 138.Description based on the following material. Twenty-one larvaereared from adults collected under a mohair bait near Kerr\dlle, KerrCo., Tex., September 29 to October 1, 1964, by Larry J. Bottimer.LI : head capsule width 1 .36 to 1 .43 mm. ; 4 specimens.LII: head capsule width 1.73 to 1.83 mm.; 4 specimens.LIII: head capsule width 1.98 to 2.30 mm.; 13 specimens.
Description of Third Stage LarvaFigure 2Cranium yellow brown to brown; with about 5 to 7 long setae neareach antenna. Postclypeus with 1 long and 1 short seta on each side.Epipharynx with about 6 stout marginal setae on each side of corypha.Haptomerum with 2 smaller sensory spots distad of 2 larger, setiferoussensory spots. Haptomerum also with 2 setae on each side caudolateradof sensory area; anterior setae smaller and closer together. Anteriorregion of pedium usually with 4 smaller sensory spots distad of arching
LARVAL TAXONOMY OF THE TROGINAE IN NORTH AMERICA 37
row of about 12 sensory' spots. Tormae with prominent anteriorepitorma and pointed pternotormae. Hypopharynx with smallerdistal area usually with 2 sensory spots distad of transverse row ofabout 12 sensory spots. Maxilla with lacinia with 3 unci and about12 to 15 marginal setae.Prothorax usually with 1 seta on anterior and posterior lateral lobes.Infraepisternal area usually with 1 seta; infraepimeral area usuallywith 2 setae.Mesothorax with about 3 to 6 setae on lateral lobe. Infraepisternalarea usually without setae ; infraepimeral area usually with 2 setae.Metathorax usually without setae on anterior lateral lobe, withabout 4 to 5 long setae on posterior lateral lobe. Infraepisternal areausually without setae ; infraepimeral area with about 1 to 2 setae.Abdomen (dorsal aspect) with DLl of segments 1 to 4 with singletransverse row of about 14 to 20 spinules, DL3 with transverse row ofabout 4 to 10 spinules. Segment 7 with transverse row of about 10 to16 spinules, often with few intermixed setae. DL2 with transverse rowof long and short setae. DL3 often with 1 or 2 small setae.Abdomen (lateral aspect) with segments 1 to 8 usually with 1 setaLLl ; LL2 with about 2 or 3 setae; LL3 usually with 1 seta.
Trox sordidus LeConteTrox sordidus LeConte, 1854, Proc. Acad. Nat. Sci. Philadelphia, vol. 7, p. 211.Description based on the following material. Sixteen larvae rearedfrom 21 adults collected at chicken remains about 4 miles north ofBronson, Sabine Co., Tex., July 7, 1964, by David R. Smith andCharles W. Baker. Three larvae collected in soil under same chickenremains by David R. Smith and Charles W. Baker.LI : head capsule width 1 .39 to 1 .46 mm. ; 5 specimens.LII : head capsule width 1 .67 to 1 .83 mm. ; 5 specimens.LIII: head capsule width 2.04 to 2.30 mm.; 9 specimens.
Description of Third Stage LarvaFigure 19Cranium deep red brown, with about 6 long setae near each an-tenna. Anterior setae of frons very short. Postclypeus with 2 setae oneach side. Epipharynx with about 6 or 7 stovit marginal setae on eachside of corypha. Haptomerum with 2 smaller sensory spots distad of 2larger, setiferous sensory spots on sensory area. Haptomerum alsowith about 2 to 4 widely separated, stout setae on each side caudo-laterad of sensory area. Anterior region of pedium usually with groupof 4 smaller sensory spots distad of slightly arching, transverse row of
38 U.S. NATIONAL MUSEUM BULLETIN 2 79
about 12 to 13 larger sensory spots. Tormae with broad anteriorepitonna and prominent pternotormae.Hypopharynx with smaller distal area with 2 sensory spots distad oftransverse row of about 1 2 to 1 6 sensory spots. Maxilla with lacinia with3 unci and about 14 to 15 marginal setae.Prothorax usually with 1 seta on anterior and posterior laterallobes. Infraepisternal and infraepimeral areas usually with 1 seta each.Mesothorax with about 3 to 4 setae on lateral lobe. Infraepisternalarea usually without setae; infraepimeral area usually with 2 setae,Metathorax usually without setae on anterior lateral lobe, with about3 to 4 long setae on posterior lateral lobe. Infraepisternal area usuallywithout setae; infraepimeral area usually with 2 setae.Abdomen (dorsal aspect) with segments 1 through 4 with transverse,irregular row or double row of about 20 to 28 spinules. DL3 withtransverse row of about 4 to 10 spinules. Segment 7 with transverseband of about 20 to 32 spinules. DL2 with about 6 to 10 scatteredspinules plus row of setae. LL3 with about 2 to 4 reduced spinules.Abdomen (lateral aspect) with segments 1 to 8 usually with 1 setaon LLl ; LL2 usually with 2 setae; LL3 usually with 1 seta on anteriorsegments, without setae on LL3 of segments 7 and 8.
Trox unistriatus BeauvoisTrox unistriatus Beauvois, 1805, Insectes receuilles ... en Amerique, p. 175,pi. 4b, fig. 5.Description based on the following material. Fourteen larvaecollected in soil beneath feathers at Raleigh, Wake Co., N. Car.,October 29, 1951, by Henry F. Howden and Paul O. Ritcher.LIII: head capsule width 2.79 to 3.08 mm.; 14 specimens.
Description of Third Stage LarvaFigures I, 7, and 42Cranium dark orange red to black, with about 6 long setae neareach antenna. Anterior setae of frons very short. Postclypeus with 2long setae on each side. Epipharynx with about 5 to 8 stout marginalsetae on each side of corypha. Haptomerum largely sclerotized, with2 to 7 setae on each side of sensory area. Sensory area usually with 2smaller sensory spots distad of 2 larger setiferous sensory spots. Hypo-pharynx with smaller distal area bearing 2 larger sensory spots distadof irregular, transverse row of about 16 to 18 smaller sensory spots.Prothorax usually with 1 or 2 setae on anterior lateral lobe andabout 1 to 3 setae on posterior lateral lobe. Infraepisternal area andinfraepimeral area usually with 1 or 2 setae.
LARVAL TAXONOMY OF THE TROGINAE IN NORTH AMERICA 39Mesothorax with about 5 to 7 setae on lateral lobe. Infraepisternalarea usually without setae; infraepimeral area with about 3 to 4 setae.Metathorax usually with 1 to 3 setae on anterior lateral lobe andabout 4 to 6 setae on posterior lateral lobe. Infraepisternal area usuallywithout setae; infraepimeral area with about 2 to 4 setae.Abdomen (dorsal aspect) with DLl of segments 1 through 4 withtransverse band of about 22 to 36 spinules; DL3 with transverse rowof about 5 to 14 spinules. Segment 7 with transverse row of about 24to 36 spinules on DLl; DL2 with transverse row of about 4 to 10spinules plus setae; DL3 usually with about 4 to 10 reduced spinules orsetae.Abdomen (lateral aspect) with segments 1 to 8 usually with 1 to 4setae on LLl ; LL2 usually with 2 to 5 setae; LL3 usually with 1 to 4setae. Generic Description of Omorgus Larvae
Larvae of this genus may be characterized as follows: Cranium(figs. 24 and 25) red brown or brown to black, reticulate posterior toposterior frontal setae, slightly rugose anterior to posterior frontalsetae. Oval, slightly raised, nonpigmented eyespot near base of eachantenna. One (rarely 2) dorsal epicranial seta on each side and 10 ormore setae near each antenna. Frons with paired posterior (lacking in0. fuliginosus), median, exterior, and anterior setae. Each anteriorangle with about 4 to 15 setae; setae usually arranged in 2 groups.Frontoclypeal suture distinct. Postclypeus as dark as or darker thancranium, with 3 (rarely 4) long setae on each side. Preclypeus lightyellow brown, glabrous. Labrum (fig. 57) synmieti'ical, darker thanpreclypeus, distal margin bilobed. With paired median, lateral, antero-lateral, and anterior setae. Antennae (figs. 2 1 and 25) three-segmented,terminal segment much reduced. Segment 2 with distal, slightly de-pressed, crescent-shaped sensory area. Segment 3 with terminal groupof 6 small sensory pegs. Epipharynx (figs. 9 and 11) with about 20 ormore stout setae along anterior border on each side of corypha. Clithrapresent. Corypha with 4 prominent setae arising from pronouncedmarginal tubercles. Haptomerum at least partially sclerotized, withcentral, elevated, lightly sclerotized sensory area usually with 2(rarely 3) smaller sensory spots slightly distad of 2 larger, setiferoussensory spots. Sensory area usually flanked by or contiguous withsmaller, lightly sclerotized area on each side. Each smaller area withsingle seta. Sclerotized portion of haptomeral region usually giving riseposteriorly to slightly curving, sclerotized band on each side of pedium.Sclerotized band less prominent anteriorly in some species, becomingmore prominent posteriorly and terminating at fused phobal mass on
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each side. Anterior region of pedium usually with 4 sensory spots distadof slightly arching, transverse row of about 12 to 20 sensory spots; the4 sensory spots widely separated, as 2 groups of 2 each, or intermixedwith main transverse row of sensory spots. Pedium with numerousphobae except in anterior median region and in posterior area betweenfused phobal masses. Pedium with fused phobal mass on each side nearposterior border. Paria with anterior and posterior group of setae oneach side. Posterior setae much stouter. Anterior setae tending tointergrade with marginal setae and posterior setae, especially on rightside of epipharynx. Setae usually more numerous on right side. Tormaesymmetrical, united medially, with prominent pternotorma on eachside. Haptolachus with 2 sclerotized, elevated plates and median sensecone. Sclerotized plates unequal; left plate smaller. Sense cone with 4sensory spots in central hyaline region. Sense cone also with small tolarge group of pigmented phobae at anterior end in some species.Central hyaline region of sense cone occasionally traversed by longi-tudinal bar. Paired macrosensillae located laterad of sense cone inmembranous area on each side. Glossa (figs. 10 and 12) with 4 sensoryspots and about 10 to 30 setae dorsally. Labial palpi two-segmented;basal segment with distal fringe of phobae on lateral aspect. Hypo-pharynx (figs. 10 and 12) divided into smaller distal area and largerproximal area. Distal area with 2 larger sensory spots distad of trans-verse row of about 14 to 23 smaller sensory spots with minute setae.Lateral areas each with slightly oblique row of densely set phobae ex-tending to base of labial palpi. Larger proximal area with symmetricalsubtormae adjoining medially and bearing paired subapotormae.Right subapotorma with prominent, dense group of phobae at apex(absent in 0. rubricans). Proximal area also with row of inwardlydirected, closely set phobae laterad of each subapotorma, row ex-tending length of proximal area. With prominent, elevated, sclerotizedprocess located anterior to point where subtormae adjoin. Maxilla(fig. 49) with galea and lacinia separate. Lacinia with 3 prominentunci, numerous stout setae along median border, and 1 to several finersetae bordering stout setae on dorsal surface. Two-segmented galeawith whorl of 5 setae at base of terminal uncus; with 1 seta at base ofgalea on ventral aspect. Four-segmented maxillary palpus with 1 setaon basal segment and 2 setae on segment 3. Stipes with 1 to 12 setae onexterior surface. Maxillary stridulatory area with longitudinal, straightrow of about 20 to 60 stridulatory teeth. Mandibles (fig. 48) darkerthan head capsule; with 2 well separated setae in dorsal exteriorgroove. Left mandible slightly longer. With small, sharp tooth (S3)proximad of scissorial notch of left mandible. With larger, roundedtooth (S2) proximad of scissorial notch of right mandible. Both man-dibleswith prominent tooth (S3 of right mandible and S4 of left mandible)on inner margin between scissorial and manducatorial areas. Addi-
LARVAL TAXONOMY OF THE TROGINAE IN NORTH AMERICA 41
tional smaller tooth (S4 of right mandible and S5 of left mandible) onventral aspect of each mandible at base of S3 and S4. Smaller teetheach with small brustia near base. Molar area of left mandible hollowedfor reception of molar area of right mandible. Each mandible withbrustia on median border near base.Prothorax (fig. 29) with prominent yellow brown to black, sclerotizedshield on each side; shield bordered with setae. Setae more numerouson anterior border. Setae continuous across dorsal nonsclerotized areabetween shields. Large lateral lobe with about 25 to 100 setae. Cribri-form spiracle located caudodorsad of lateral lobe ; concavity of respira-tory plate directed anteroventrally. Sterum with to about 20 setaeon each of 2 weak, transverse lobes.Mesothorax (fig. 29) divided dorsally into larger anterior lobe andsmaller posterior lobe. Anterior lobe with transverse band of numeroussetae; posterior lobe with transverse row of about 8 to 18 setae. Largelateral lobe v/ith about 20 to 85 setae. Sternum with 2 groups of setae,with about 6 to 50 setae in each group.Metathorax (fig. 29) also divided dorsally into larger anterior lobeand smaller posterior lobe. Anterior lobe with transverse band ofnumerous setae; posterior lobe with transverse row of about 8 to 18spinules and about 4 to 12 setae. With 2 lateral lobes; smaller anteriorlobe with about 5 to 25 setae and larger posterior lobe with about17 to 60 setae. Sternum with 2 groups of setae; anterior transverseband with about 7 to 60 setae; posterior patch with about 7 to 50 setae.Infraepisternal area usually with 1 to 10 setae on prothorax; withor without as many as 8 setae on mesothorax and metathorax. Infra-epimeral area of prothorax with about 2 to 20 setae ; with about 8 to40 setae on both mesothorax and metathorax.Legs (fig. 27) four-segmented and subequal, increasing slightly inlength posteriorly. Short setae numerous on all four segments; longsetae only on 2 basal segments. Each leg with long terminal claw with2 setae. Tibiotarsus with terminal whorl of 6 setae plus about 15 to 22setae proximad of whorl.Abdomen (dorsal aspect, fig. 33) with segments 1 through 8 with3 dorsal lobes (DLl, DL2, and DL3) and lateral cribriform spiracles.Spiracles subequal, with concavity of respiratory plate directed antero-ventrally. Segments 1 through 6 with similar setal pattern. DLl withtransverse row of spinules usually flanked anteriorly and posteriorlyby short, fine setae (absent in at least 2 species). DL2 with transverserow of spinules plus setae. Long and short setae occur posterior tospinules but only short setae occur anterior to spinules, setae becomingmore numerous laterally and often intergrading with setae of spiracularlobe. DL3 with row of spinules plus setae. Long setae occur posteriorto spinules on segments 1 to 4 and anterior to spinules on segments5 and 6. When present, short setae occur anterior to spinules on
42 U.S. NATIONAL MUSEUM BULLETIN 279
segments 1 to 4 and posterior to spinules on segments 5 and 6. DL3also with 3 associated dorsal-lateral lobes (DL3a, DL3b, and DL3c,fig. 33). DL3a and DL3c with few setae; DL3b with few setae plusspinules, spinules more numerous on segments 4 to 6. DL3c partiallycoalesced with DL3 in segment 5. DL3a, DL3b, and DL3c at leastpartially coalesced with DL3 in segment 6; greatly reduced or lackingposterior to segment 6. Segment 7 with transverse row of about 4 to 20spinules plus setae on DLL Setae absent in some species. DL2 andDL3 of segment 7 with transverse band of setae. Segment 8 withtransverse row of setae on DLL DL2 and DL3 with transverse band ofnumerous setae. Segment 9 with 2 transverse rows of setae ; setae morenumerous in posterior row. Segment 10 without subdivisions, withbroad band of caudally directed, spiniform setae ; longer anterior andposterior setae organized into rather discrete rows.Abdomen (lateral aspect, fig. 33) with 3 distinct setae-bearing lobes(LLl, LL2, and LL3) on segments 1 through 8. Setae on each respec-tive lobe usually decreasing in number posteriorly from about segment3 to segment 8. Segment 9 normally with only 2 lateral lobes. Segment10 with band of numerous spiniform setae; band slightly depressed onanterior border opposite LL2 of segment 9.Abdomen (ventral aspect, figs. 28 and 33) with 3 distinct setae-bearing lobes (VLl, VL2, and VL3) on segments 1 through 8. VLlwith or without fine setae on segments 1 through 5; without setae onsegments 6 through 9. VL3 constricted in median region, expandedlaterally, with group of setae on each side. Each group of setae usuallyseparated into subgroups by weakly impressed, longitudinal fold.Number and size of setae and size of lobes on ventral aspect usuallydecreasing progressively from about segment 3 to segment 9. Segment9 usually with about one-half as many setae as found on anterior seg-ments. Segment 10 with broad band of caudally directed, spiniformsetae; band narrowly discontinuous at median line. Anal openingsurrounded by single dorsal lobe and 2 larger ventral lobes (fig. 51).
Species Descriptions of Omorgus LarvaeOmorgus suberosus (Fabricius)Trox suberosus Fabricius, 1775, Systema entomologiae, p. 3LDescription based on the following material. Eight larvae rearedfrom 4 adults taken at black light about 2.5 miles east of Hermiston,Umatilla Co., Oreg., June 11-13, 1963, by Charles W. Baker. Tenlarvae reared from 3 adults collected at black light about 1.0 milesouth of Hermiston, Umatilla Co., Oreg., June 18, 1963, by William
LARVAL TAXONOMY OF THE TROGINAE IN NORTH AMERICA 43
P. Stephen and Charles E. Osgood. Three larvae reared from singleadult collected at a dried coyote carcass about 2.0 miles east of Rodeo,Hildago Co., N. Mex., August 7, 1963, by Noel McFarland andChris Schuberth.LI: head capsule width 2.11 to 2.15 mm.; 2 specimens.LII: head capsule width 2.85 to 2.90 mm.; 2 specimens.LIII: head capsule width 3.60 to 4.48 mm.; 17 specimens.
Description of Third Stage LarvaFigure 1
1
Cranium light red brown to dark red brown, with about 12 to 18setae near each antenna. Each anterior angle of frons with about5 to 8 setae. Epipharynx with about 20 stout setae near anteriorborder on each side of corypha. With group of phobae mediad offused phobal mass on right side. Paria with about 8 to 14 posteriorsetae and about 15 to 22 anterior setae on each side. Glossa with 4sensory spots and about 14 to 16 setae dorsally; with 2 sensory spotsand 2 long setae ventrally. Maxilla with sdpes bearing 1 to 3 setaeon exterior surface. Maxillary stridulatory area with longitudinal rowof about 16 to 22 stridulatory teeth.Prothorax with about 40 to 50 setae on lateral lobe. Infraepistemalarea with about 1 to 4 setae; infraepimeral area with about 7 to 17setae.Mesothorax with about 30 to 50 setae on lateral lobe. Infraepistemalarea usually without setae ; infraepimeral area with about 15 to 23 setae.Metathorax with transverse row of about 14 to 18 spinules and 4 to 7setae on smaller dorsal lobe (DL2). Anterior lateral lobe (LLl) withabout 9 to 13 setae. Posterior lateral lobe (LL2) with about 25 to 60setae. Infraepistemal area usually with 1 to 3 setae; infraepimeral areawith about 19 to 22 setae.Legs with each tibiotarsus with terminal whorl of 6 setae plus about9 to 1 1 setae proximad of whorl.Abdomen with transverse row of about 10 to 16 spinules plus setaeon DL 1 of segmicnt 7.
Omorgus fuliginosus (Robinson)Trox (Omorgus) fuliginosus Rohinson, 1941, Ent. News, vol. 52, p. 134.Description based on the following material. Twenty-one larvaereared from 1 female and 5 males collected under 2 deer carcasses1.0 mile south of Uvalde, Uvalde Co., Tex., June 29, 1964, by DavidR. Smith and Charles W. Baker.285-935?63 4
44 U.S. NATIONAL MUSEUIVI BULLETEN 2 79LI: head capsule width 2.64 to 2.85 mm.; 4 specim.ens.LII: head capsule width 3.52 mm.; 2 specimens.LIII: head capsule width 4.04 to 4.83 mm.; 15 specimens.
Description of Third Stage LarvaFigures 29 and 57Cranium dull red brown, with about 11 to 1 8 setae near each antenna.Frons without posterior frontal setae. Each anterior angle of fronswith about 3 to 7 setae. Epipharyns with about 16 to 22 stout setaenear anterior border on each side of cory^ha. Paria with about 19 to 32anterior setae and about 7 to 11 stouter posterior setae on each side.Glossa with 4 sensory spots and about 13 to 17 setae dorsally; with2 sensory spots and 2 long setae ventrally. Maxilla with stipes bearingI to 3 setae on exterior surface. Maxillary stridulatory area withlongitudinal row of about 15 to 20 stridulatory teeth.Prothorax with about 30 to 45 setae on lateral lobe. With 1 seta oninfraepisternal area; infracpimeral area with about 6 to 10 setae.Mesothorax with about 22 to 30 setae on lateral lobe. Infraepisternalarea usually without setae; infracpimeral area with about 10 to 14setae.Metathorax with transverse row of about 1 2 spinules and 4 setae onsmaller dorsal lobe (DL2). Anterior lateral lobe (LLl) with about 7 toII setae. Posterior lateral lobe (LL2) with about 21 to 25 setae. Infra-episternal area usually without setae; infracpimeral area with about10 to 14 setae.Legs with each tibiotarsus with terminal whorl of 6 setae plus about14 to 18 setae proximad of whorl.Abdomen with transverse row of spinules on DLl of segments 1through 6. Segment 7 with transverse row of spinules posterior to rowof sparse setae on DLl.Qmorgus monachus (Herbst)Trox monachus herbst, 1 790, Natursystem aller bekannten inund auslandischenInsekten, vol. 3, p. 25, pi. 21, fig. 7.Description based on the following material. Thirteen larvae rearedfrom 2 adults collected under an old crow carcass at the Boyce Thomp-son Institute Forest Research Laboratory, Hardin Co., Tex., May 12,1964, by Robert I. Gara. Eight larvae collected beneath a pile ofchicken feathers 4.0 miles north of Bronson, Sabine Co., Tex., July 7,1964, by David R. Smith and Charles W. Baker.
LARVAL TAXONOMY OF THE TROGESTAE IN NORTH AMERICA 45LI : head capsule width 2.46 to 2.55 mm. ; 5 specimens.LII: head capsule width 3.43 mm.; 1 specimen.LIII: head capsule width 4.04 to 4.75 mm.; 15 specimens.
Description of Third Stage LarvaFigures 13, 14, 23, 24, 30, 32, 33, 34, and 59Cranium dark red brown, with about 12 to 16 setae neareach antenna. Each anterior angle of frons with about 4 to 6 setae.Epipharynx with about 20 stout setae near anterior border on eachside of corypha. Paria with about 12 to 24 anterior setae and about7 to 14 stouter posterior setae on each side. Glossa with 4 sensoryspots and about 14 to 20 setae dorsally; with 2 sensory spots and 2long setae ventrally. Maxilla with stipes bearing 1 to 3 setae on exteriorsurface. Maxillary stridulatory area with longitudinal row of about14 to 26 stridulatory teeth.Prothorax with about 25 to 32 setae on lateral lobe. Infraepisternalarea usually with 1 seta; infraepimeral area with about 5 to 7 setae.Mesothorax with about 20 to 30 setae on lateral lobe. Infraepisternalarea usually lacking setae; infraepimeral area with about 8 to 12 setae.Metathorax with transverse row of about 14 to 18 spinules and setaeon smaller dorsal lobe (DL2). Anterior lateral lobe (LLl) with about5 to 10 setae. Posterior lateral lobe (LL2) wdth about 17 to 22 setae.Infraepisternal area usually without setae; infraepimeral area withabout 10 to 12 setae.Legs with each tibiotarsus with terminal whorl of 6 setae plus about11 to 15 setae proximad of whorl.Abdomen with transverse row of spinules on DLl of segments 1through 6. Segment 7 with transverse row of about 14 to 18 intermixedspinules and setae on DLl.
Omorgus asper LeConteOmorgus asper LeConte, 1854, Proc. Acad. Nat. Sci. Philadelphia, vol. 7, p. 215.Description based on the following material. Twenty-two larvaereared from 4 adults collected under an old crow carcass at the BoyceThompson Institute Forest Research Laboratory, Hardin Co., Tex.,May 12, 1964, by Robert I. Gara.LI: head capsule width 2.10 to 2.30 mm.; 8 specimens.LII: head capsule width 2.81 to 3.30 mm.; 5 specimens.LIII: head capsule width 3.60 to 4.04 mm.; 9 specimens.
46 U.S. NATIONAL MUSEUM BULLETIN 2 79Description of Third Stage LarvaFigure 21Cranium dark brown to black, with about 13 to 18 setae near eacliantenna. Each anterior angle of frons with about 7 to 10 setae. Epl-pharynx with about 17 to 21 stout setae near anterior border on eachside of corypha. Paria with about 10 to 25 anterior setae and about 6to 13 stouter posterior setae on each side. Glossa with 4 sensory spotsand about 12 to 16 setae dorsally; with 2 sensory spots and 2 longsetae ventrally. Maxilla with stipes bearing 1 to 3 setae on exteriorsurface. Maxillary stridulatory area with longitudinal row of about20 to 30 stridulatory teeth.Prothorax with about 35 to 50 setae on lateral lobe. Infraepisternalarea with about 2 to 5 setae; infraepimeral area with about 8 to 13setae.Mesothorax with about 30 to 45 setae on lateral lobe. Infraepisternalarea usually without setae; infraepimeral area with about 18 to 24setae.Metathorax with transverse row of about 7 to 14 spinules and 3to 7 setae on smaller dorsal lobe (DL2). Anterior lateral lobe (LLl)with about 8 to 14 setae. Posterior lateral lobe (LL2) with about30 to 36 setae. Infraepisternal area with to about 6 setae; infra-epimeral area with about 18 to 20 setae.Legs with each tibiotarsus with terminal whorl of 6 setae plusabout 8 to 1 2 setae proximad of whorl.Abdomen with transverse row of about 5 to 1 spinules and about20 to 30 setae on DLl of segment 7.
Omorgus inflatus (Loomis)
Trox inflatus Loomis, 1922, Journ. Washington Acad. Sci., vol. 12, p. 135,fig. 1.Description based on the following material. Five larvae reared from1 female collected at a dried coyote carcass about 2.0 miles east ofRodeo, Hildago Co., N. Mex., August 7, 1963, by Noel McFarlandand Chris Schuberth. Three larvae reared from 1 female collectedunder a coyote carcass about 3.0 miles east of La Luz, Otero Co.,N. Mex., July 22, 1964, by David R. Smith and Charles W. Baker.LI: head capsule width 2.20 mm.; 1 specimen.LIII: head capsule width 3.96 to 4.48 mm.; 7 specimens.
LARVAL TAXONOMY OF THE TROGINAE IN NORTH AMERICA 47Description of Third Stage LarvaFigure 26Cranium dark red brown, with about 16 to 24 setae near eachantenna. Each anterior angle of frons with about 7 to 1 1 setae. Epi-pharynx with about 18 to 25 stout setae near anterior border on eachside of corypha. Paria with about 10 to 25 anterior setae and about7 to 12 stouter posterior setae on each side. Glossa with 4 sensory spotsand about 18 to 20 setae dorsally; with 2 sensory spots and 2 long setaeventrally. Maxilla with stipes bearing 1 to 4 setae on exterior surface.Maxillary stridulatory area with longitudinal row of about 20 to 30stridulatory teeth. Lacinia with 1 or 2 exterior setae.Prothorax with about 65 to 80 setae on lateral lobe. Infraepisternalarea with about 6 to 10 setae; infraepimeral area with about 15 to20 setae.Mesothorax with about 50 to 85 setae on lateral lobe. Infraepisternalarea usually with 1 to 4 setae; infraepimeral area with about 28 to40 setae.Metathorax with transverse row of about 9 to 15 spinules and 8 to12 setae on smaller dorsal lobe (DL2). Anterior lateral lobe (LLl)with about 20 to 30 setae. Posterior lateral lobe (LL2) with about55 to 75 setae. Infraepisternal area with about 4 to 7 setae; infraepimeralarea with about 30 to 44 setae.Legs with each tibiotarsus with terminal whorl of 6 setae plus about12 to 16 setae proximad of whorl.Abdomen with transverse row of about 13 to 20 spinules and 20 to35 setae on DLl of segment 7.Omorgus punctatus (Germar)
Trox punctatus Germar, 1824, Insectorum species novae, vol. I, p. 113.Description based on the following material. Six larvae reared from2 females collected at cow carcasses within 10 miles of Rodeo, HildagoCo., N. Mex., July 24-26, 1964, by David R. Smith and Charles W.Baker.LIII: head capsule width 3.69 to 4.04 mm.; 6 specimens.
Description oj Third Stage LarvaFigure 27Cranium dark red brown to black, with about 15 to 20 setae neareach antenna. Each anterior angle of frons with about 7 to 9 setae.
48 U.S. NATIONAL MUSEUM BULLETIN 2 79Epipharynx with about 18 to 24 setae near anterior border on eachside of corypha. Paria with about 15 to 25 anterior setae and about10 to 15 stouter posterior setae on each side. Glossa with 4 sensoryspots and about 12 to 16 setae dorsally; with 2 sensory spots and 2long setae ventrally. Maxilla with stipes bearing about 1 to 4 setae onexterior surface. Maxillary stridulatory area with longitudinal row ofabout 15 to 30 stridulatory teeth.Prothorax with about 45 to 60 setae on lateral lobe. Infraepisternalarea with about 3 to 5 setae; infraepimeral area with about 14 to 18setae.Mesothorax with about 35 to 50 setae on lateral lobe. Infraepisternalarea with to about 2 setae; infraepimeral area with about 24 to 32setae.Metathorax with transverse row of about 10 to 15 spinules and about4 to 8 setae on smaller dorsal lobe (DL2). Anterior lateral lobe (LLl)with about 10 to 14 setae; posterior lateral lobe (LL2) with about 25to 40 setae. Infraepisternal area with to about 2 setae; infraepimeralarea with 20 to 25 setae.Legs with each tibiotarsus with terminal w horl of 6 setae plus about12 to 15 setae proximad of whorl.Abdomen with transverse row of about 1 5 to 20 spinules and about16 to 30 setae on DLl of segment 7.Omorgus carinatus (Loomis)Trox carinatus Loomis, 1922, Journ. Washington Acad. Sci., vol. 12, p. 135,fig. 1.Description based on the following material. Twenty-three larvaereared from 6 adults collected at a dried coyote carcass about 2.0 mileseast of Rodeo, Hildago Co., N. Mex., August 7, 1963, by Noel Mc-Farland and Chris Schuberth.LI: head capsule width 2.20 to 2.28 mm.; 3 specimens.LII: head capsule width 2.99 to 3.08 mm.; 4 specimens.LIII: head capsule width 3.78 to 4.22 mm.; 16 specimens.
Description of Third Stage LarvaFigures 12 and 28Cranium dark red brown to black, with about 14 to 23 setae neareach antenna. Each anterior angle of frons with about 6 to 9 setae.Epipharynx with about 20 stout marginal setae near anterior borderon each side of corypha. Paria with about 12 to 25 anterior setae andabout 9 to 14 stouter posterior setae on each side. Median sense coneof haptolachus with small group of phobae at anterior end. Glossa
LARVAL TAXONOMY OF THE TKOGINAE IN NORTH AMERICA 49
with 4 sensory spots and about 14 to 18 setae dorsally; with 2 sensoryspots and 2 long setae ventrally. Maxilla with stipes bearing 1 to 3setae on exterior surface. Maxillary stridulatory area with longitudinalrow of about 20 to 30 teeth.Prothorax with about 50 to 65 setae on lateral lobe. Infraepisternalarea with about 1 to 5 setae; infraepimeral area with about 8 to 12setae.Mesothorax with about 30 to 50 setae on lateral lobe. Infraepisternalarea with to 2 setae ; infraepimeral area with about 15 to 21 setae.Metathorax with transverse row of about 10 to 14 spinules and 4to 6 setae on smaller dorsal lobe (DL2). Anterior lateral lobe (LLl)with about 10 to 20 setae. Posterior lateral lobe (LL2) with about 30to 45 setae. Infraepisternal area with to 3 setae; infraepimeral areawith about 13 to 20 setae.Legs with each tibiotarsus with terminal whorl of 6 setae plus about1 to 13 setae proximad of whorl.Abdomen with transverse row of about 8 to 12 spinules and about25 to 40 setae on DLl of segment 7.
Omorgus scutellaris (Say)Trox scutellaris Say, 1823, Journ. Acad. Nat. Sci. Philadelphia, vol. 3, p. 238.Description based on the following material. Eight larvae reared from1 female collected in soil under a rabbit carcass 1 mile west of Valentine,Jeff Davis Co., Tex., June 26, 1964, by David R. Smith and Charles W.Baker. One larva reared from 1 female collected under a buzzardcarcass 1 mile west of Valentine, Jeff Davis Co., Tex., June 26, 1964,by David R. Smith and Charles W. Baker. Three larvae reared froman aggregation of adults collected by David R. Smith and Charles W.Baker as follows: at a cow carcass about 18 miles south of Rodeo,Hildago Co., N. Mex., July 25, 1964; at a buzzard carcass about5.0 miles north of Rodeo, Hildago Co., N. Mex., July 24, 1964; at acow carcass about 6.0 miles east of Portal, Cochise Co., Ariz., July 25,1964.LII: head capsule width 4.23 to 4.41 mm.; 2 specimens.LIII: head capsule width 5.04 to 5.85 mm.; 10 specimens.
Description of Third Stage LarvaFigures 9, 48, 50, and 51Cranium dark red bro\vn to black, with 1 or 2 dorsal epicranialsetae on each side and about 18 to 28 setae near each antenna. Eachanterior angle of frons with about 8 to 10 setae. Postclypeus with
50 U.S. NATIONAL MUSEUM BULLETIN 2793 or 4 setae oa eacli side. Epipharynx with more than 2U stout setaenear anterior border on each side of corypha. Sensory area of hap-tomerum often partially or entirely divided by sclerotized area into2 areas with 2 sensory spots each. Paria with about 30 to 60 anteriorsetae and about 10 to 14 stouter posterior setae on each side. Sensecone of haptolachus with small clump of phobae at anterior end.Glossa with 4 sensory spots and about 15 to 21 setae dorsally; with2 sensory spots and 2 long setae ventrally. Maxilla with stipes bearing3 to 8 setae on exterior surface. Maxillary stridulatory area withlongitudinal row of about 35 to 45 stridulatory teeth.Prothorax with about 60 to 80 setae on lateral lobe. Infraepisternalarea with about 3 to 5 setae; infraepimeral area with about 15 to 20setae.Mesothorax with about 50 to 65 setae on lateral lobe. Infraepisternalarea with 1 or 2 setae; infraepimeral area with about 22 to 30 setae.Metathorax with transverse row of about 9 to 1 7 spinules and 4 to8 setae on smaller dorsal lobe (DL2). Anterior lateral lobe (LLl)with about 14 to 21 setae. Posterior lateral lobe (LL2) with about40 to 45 setae. Infraepisternal area usually without setae; infraepi-meral area with about 20 to 30 setae.Legs with each tibiotarsus with terminal whorl of 6 setae plus about15 to 22 setae proximad of whorl.Abdomen with transverse band of about 8 to 14 spinules and about45 to 60 setae on DLl of segment 7.Omorgus rubricans (Robinson)Trox {Omorgus) rubricans Robinson, 1946, Trans. Amcr. Ent. Soc, vol. 72, p. 57.Description based on the following material. Eighteen larvae rearedfrom 13 adults collected under a fawn carcass on the Rob and BessieWelder Wildlife Foundation, San Patricio Co., Tex., July 10, 1964,by Charles W. Baker and David R. Smith.LI: head capsule width 2.72 mm.; 1 specimen.LII: head capsule width 3.25 to 3.60 mm.; 2 specimens.LIII: head capsule width 4.04 to 4.65 mm.; 15 specimens.
Description of Third Stage LarvaFigure 10Cranium dark brown, with about 15 to 20 setae near each antenna.With pronounced concavity mediad of eyespot. Concavity about samesize as eyespot, with single seta. Anterior border of concavity declivous;
LARVAL TAXONOMY OF THE TKOGINAE IN NORTH AMERICA 51posterior border vertical. Each anterior angle of frons with about 5 to8 setae. Epipharynx with about 1 8 to 24 setae near anterior border oneach side of corypha. Sclerotization of haptomeral region most pro-nounced just anterior to sensory spots of pedium in form of prominenttransverse band. Sclerotized band on each side of pedium reduced inanterior region, becoming more pronounced posteriorly. Usually witha few small phobae posterior to each fused phobal mass. Paria withabout 18 to 30 anterior setae and about 6 to 10 stouter posterior setaeon each side. Sense cone of haptolachus with central hyaline regionoften traversed by median longitudinal, darkened area. Glossa with 4sensory spots and about 8 to 12 setae dorsally; with 2 sensory spots and2 long setae ventrally. Hypopharynx with transverse band of caudallydirected phobae at base of smaller distal area; without phobal patchat end of right subapotorma. Maxilla with stipes bearing 1 to 4 setaeon exterior surface. Maxillary stridulatory area with longitudinal rowof about 18 to 30 stridulatory teeth.Prothorax with about 45 to 60 setae on lateral lobe. Infraepisternalarea with about 2 setae; infraepimeral area with about 10 to 15 setae.Mesothorax with about 36 to 50 setae on lateral lobe. Infraepi-sternal area usually devoid of setae ; infraepimeral area with about 20to 25 setae.Metathorax with transverse row of about 8 to 10 spinules and 4 to 6setae on smaller dorsal lobe (DL2). Anterior lateral lobe (LLl) withabout 12 to 15 setae. Posterior lateral lobe (LL2) with about 30 to 38setae. Infraepisternal area with 1 to 2 setae; infraepimeral area withabout 20 to 24 setae.Legs with each tibiotarsus with terminal whorl of 6 setae plus about14 to 18 setae proximad of whorl.Abdomen with transverse rov/ of about 22 to 26 setae and 5 to 7spinules on DLl of segment 7.
Omorgus texanus LeConteOmorgus texanus LeConte, 1854, Proc. Acad. Nat. Sci. Philadelphia, vol. 7,p. 214.Description based on following material. Sixteen larvae reared fromadults collected at cow and javelina carcasses, and single larvaecollected under a sheep carcass and a javelina carcass about 0.5 mileeast of Hebbronville, Jim Hogg Co., Tex., July 13-15, 1964, by DavidR. Smith and Charles W. Baker.LI: head capsule width 4.50 mm.; 2 specimens.LII: head capsule width 4.95 to 5.40 mm.; 3 specimens.LIII: head capsule width 5.85 to 6.93 mm.; 13 specimens.
62 U.S. NATIONAL MUSEUM BULLETIN 2 79Description of Third Stage LarvaFigures 23, 25, and 49Cranium fuscous to black, with about 30 to 40 setae near eachantenna. Pronounced concavity mediad of eyespot. Concavity aboutsame size as eyespot, with single seta. Anterior border of concavitydeclivous; posterior border vertical. Each anterior angle of frons withabout 10 to 15 setae. Epipharynx with about 30 to 40 long setae nearanterior border on each side of corypha. Right side of haptomerumoften more heavily sclerotized. Usually with small group of phobaeon each side mediad of fused phobal mass and distad of torma;group on right usually more pronounced. Paria usually with morethan 60 setae on each side. Setae not readily separated into anteriorand posterior groups. Sense cone of haptolachus with group of pig-mented phobae at anterior end. Glossa with 4 sensory spots and about24 to 30 setae dorsally, dorsal setae intergrading with ventral setae.Hypopharynx with smaller distal area bearing group of caudallydirected phobae at base between lateral, oblique rows of phobae.Maxilla with galea bearing 5 to 8 fine setae on dorsal aspect in additionto whorl of 5 setae at base of terminal uncus. Stipes with about 8 to11 setae on exterior border. Maxillary stridulatory area with about33 to 60 stridulatory teeth.Prothorax with about 80 to 100 setae on lateral lobe. Infraepisternalarea with about 1 to 4 setae; infraepimeral area with about 10 to 14setae.Mesothorax with about 55 to 75 setae on lateral lobe. Infraepisternalarea with to 2 setae; infraepimeral area with about 31 setae.Metathorax with transverse row of about 7 setae and 7 spinules onsmaller dorsal lobe (DL2). Anterior lateral lobe (LLl) with about20 to 25 setae. Posterior lateral lobe (LL2) with about 40 to 70 setae.Infraepisternal area usually without setae; infraepimeral area withabout 35 setae.Legs with each tibiotarsus with an average of about 23 setae inaddition to terminal whorl of 6 setae.Abdomen with about 4 small spinules and numerous short and longsetae on DLl of segment 7.
LARVAL TAXONOMY OF THE TROGINAE IN NORTH AMERICA 53Summary
1. The adults of 12 species of Trox and of 10 species of Omorgus werecollected from the spring of 1963, through the spring of 1965, and thelarvae reared in the laboratory.2. Collections of adult Glaresis were made in Oregon, but all attemptsto rear larvae in the laboratory failed.3. A mixture of cow hair, deer hair, sheep's wool, rabbit hair andskin, and pheasant, quail, and dove feathers and skin was foundsufficient for rearing the 22 species.4. The suberosus group, one of five groups of species within the genusTrox in North America as recognized by Vaurie (1955), is givengeneric status. The other four groups, scaber, terrestris^ luberculatus, andunistriatus, are retained in the genus Trox.5. Seventeen morphological differences were found for separatingthe genera Trox and Omorgus.6. Generic descriptions for the third stage larvae of Trox and Omorgusare presented.7. Third stage larvae of 14 species of Trox are described; 10 of themfor the first time.8. Third stage larvae of 10 species of Omorgus are described; 8 ofthem for the first time.9. Keys for separating the third stage larvae of Trox from thoseof Omorgus and for separating the third stage larvae of each genus arepresented. Larvae of several closely related species were inseparableand are brought out in the same couplet.10. The general biology of the adults and larvae is described on thebasis of laboratory studies and field notes.11. The life history of T. scaber (L.) is described as it occurred in thelaboratory, and notes on several other species are given.12. Third stage larvae of the scaber group and the terrestris group werefound to possess group specific characteristics.13. The unistriatus and tuberculatus groups could not be separated bylarval characters.14. Based on larval morphology there are species groups within thegenus Omorgus,15. The pertinent morphological structures are illustrated in 59figures.16. The lobes of the thorax and abdomen are named according to anew, simplified system, and the terms subtorma, subapotorma, andfused phobal mass are coined to facilitate the description of the epi-pharynx and hypopharynx.

Literature Cited
Arnett, R. H., Jr.1960. The beetles of the United States, 1 112 pp.Balthasar, V.1936. Monogi-aphie der Subfamilie Troginae der palaearktischen Region.In Festschrift zum 60, pp. 407-459.BoviNG, A. G.1936. Description of the larva of Plectris aliena Chapin and explanation ofnew terms applied to the epipharynx and raster. Proc. Ent. Soc.Washington, vol. 38, pp. 169-185.1942. A classification of larvae and adults of the genus Phyllophaga. Mem.Ent. Soc. Washington, vol. 2, pp. 1-95.BoviNG, A. G., and Craighead, F. C.1931. An illustrated synopsis of the principal larval forms of the orderColeoptera. Entomologia Americana, n. s., vol. 11, nos. 1-4,pp. 1-351.Crowson, R. a.1955. The natural classification of the families of Coleoptera, 187 pp.Denier, P.1936. Estado actual de mis conocimientos acerca del "champi" {Troxsuberosus F.). In Mem. Com. Cent. Invest. Langosta, pp. 205-2 1 6.Edv^^ards, J. G.1949. Coleoptera or beetles east of the great plains, 181 pp.Erichson, W. F.1847. Conspectus insectorum coleopterorum quae in Republica Peruanaobservata sunt. Archiv fiir Naturgeschichte, vol. 13, no. 1, pp.67-185.Fabr6, J. H.1903. Souvenirs entomologiques. Etudes sur I'instinct et les moeurs desinsectes, Huitieme Serie, 378 pp.Gardner, J. C. M.1946. A note on the larva of Trox procerus Har. (Scarabaeidae, Col.).(1947) Indian Journ. Ent., vol. 8, pp. 31-32.Haaf, E.1953. Die afrikanischen Arten der Gattung Trox F. I. Beitrag zurKenntnis der Subfam. Troginae. Ent. Arb. Mus. G. Frey, vol. 4,pp. 309-346. 55
56 U-S. NATIONAL MUSEUM BULLETIN 2 791954a. Die afrikanischen und orientalischen Arten der Gattung Trox. II.Beitrag zur Kenntnis der Subfam. Troginae. Ent. Arb. Mus. G.Frey, vol. 5, pp. 326-393.1954b. Die australischen Arten der Gattung Trox. III. Beitrag zurKenntnis der Subfam. Troginae. Ent. Arb. Mus. G. Frey, vol. 5,pp. 691-740.Hayes, W. P.1929. Morphology, taxonomy and biology of larval Scarabaeoidea.Illinois Biological Monographs, vol. 12, no. 2, pp. 1-119.Hayward, K. J.1936. Contribucion al conocimiento de la langosta Schistocerca paranensisBurm. y sus enemigos naturales. In Mem. Com. Cent. Invest.Langosta, pp. 217-229.Henriksen, K. L.1925. Torbistlarverne. Danmarks Fauna, vol. 29, pp. 125-170.Hicks, E. A.1959. Check-list and bibliography on the occurrence of insects in bird'snests, 681 pp.HOWDEN, H. F.1955. Biology and taxonomy of North American beetles of the subfamilyGeotrupinae with revisions of the genera Bolbocerosoma, Eucanthus,Geotrupes and Peltotrupes {Scarabaeidae). Proc. U.S. Nat. Mus.,vol. 104, no. 3342, pp. 151-319.HowDEN, H. F., and Vaurie, P.1957. Two new species of Trox from Florida (Coleoptera, Scarabaeidae).Amer. Mus. Novitates, no. 1818, pp. 1-6.Jerath, M. L.1960. Notes on larvae of nine genera of Aphodiinae in the United States(Coleoptera: Scarabaeidae). Proc. U. S. Nat. Mus., vol. Ill,no. 3425, pp. 43-94.Lacordaire, J. T.1856. Histoire naturelle dcs insectes, 12 vols.LeConte, J. L.1854. Descriptions of the species of Trox and Omorgus inhabiting theUnited States. Proc. Acad, Nat. Sci. Philadelphia, vol. 7, pp.211-216.Leefmans, S.1932. Biologische gegevens van een in grotten levenden Trox uit Zuid-Celebes {Trox costatus Wied. var.). Tijdschrift voor Entomologie,vol. 75, pp. 36-43.Meinert, F.1895. Sideorganerne hos scarabae-larverne. Det Kgl. Danske Videnska-bernes Selskabs Skrifter, 6. Raekke, naturvidenskabelig ogmathematisk afdeling, vol. 8, no. 1, pp. 3-72.Panin, S.1957. Fauna Republicii Populare Romine. Insecta: Coleoptera, FamiliaScarabaeidae, vol. 10, no. 4, pp. 1-315.
LARVAL TAXONOMY OF THE TROGINAE IN NORTH AJMERICA 57Paulian, R.1943. Les coleoptcres, 39G pp.1956. Atlas des larves d'insectes de France, 222 pp.PerriSj E.1877. Larves des coleoptcres: lamellicorns et pectinicorns. Ann. Soc.Linn. Lyon, vol. 22, pp. 91-122.Peterson, A.1951. Larvae of insects. Part II, 416 pp.RiTCHER, P. O.1944. Dynastinae of North Ameiica with descriptions of the larvae andkeys to genera and species (Coleoptera: Scarabaeidae) . KentuckyAgric. Exp. Sta. Bull. 467, pp. 1-56.1945a. Rutelinae of eastern North America with descriptions of the larvaeof Strigodermella pygmaea (Fab.) and three species of the tribeRutelini (Coleoptera: Scarabaeidae). Kentucky Agric. Exp. Sta.Bull. 471, pp. 1-19.1945b. North American Cetoniinae with descriptions of their larvae andkeys to genera and species (Coleoptera: Scarabaeidae). KentuckyAgric. Exp. Sta. Bull. 476, pp. 1-39.1 945c. Coprinae of eastern North America with descriptions of larvae andkeys to genera and species (Coleoptera: Scarabaeidae). KentuckyAgric. Exp. Sta. Bull. 477, pp. 1-23.1947. Larvae of Geotrupinae with keys to ti-ibes and genera (Coleoptera:Scarabaeidae). Kentucky Agric. Exp. Sta. Bull. 506, pp. 1-27.1949. Larvae of Melolonthinae with keys to tribes and genera (Coleoptera:Scarabaeidae). Kentucky Agric. Exp. Sta. Bull. 537, pp. 1-36.1966. White grubs and their allies. A study of North American scarabaeoidlarvae. Oregon State Monographs, Studies in Entomology no. 4,214 pp.ROFFEY, J.1958. Observations on the biology of Trox procerus Har. (Coleoptera,Trogidae), a predator of eggs of the desert locust, Schistocercagregaria (Forsk.). Bull. Ent. Res., vol. 49, pp. 449-465.SCHIODTE, J. C.1874. De metamorphosi eleutheratorum observationes: bidrag til insek-ternes udviklingshistorie. Naturhistorisk Tidsskrift, vol. 9, pp.227-376.Sharp, D., and Mihr, F.1912. The comparative anatomy of the male genital tube in Coleoptera.Trans. Ent. Soc. London, vol. 72, pp. 49-59.Sim, R. J.1934. Characters useful in distinguishing larvae of Popillia jcponica andother introduced Scarabaeidae from native species. U.S. Dept.Agric. Circ. 334, pp. 1-20.Spector, W.1943. Collecting beetles {Trox) with feather bait traps (Coleoptera:Scarabaeidae). Ent. News, vol. 54, no. 9, pp. 224-229.
58 U.S. NATIONAL MUSEUM BULLETIN 279VAN Emden, ?. 1.1941. Larvae of British beetles. II. A key to the British lamcllicornialarvae. Ent. Monthly Mag., vol. 77, pp. 117-127, 181-192.1948. A Trox larva feeding on locust eggs in Somalia. Proc. R. Ent. Soc.London, (B), vol. 17, nos. 11-12, pp. 145-148.Vaurie, p.1955. A revision of the genus Trox in North America (Coleoptera:Scarabaeidae) . Bull. Amer. Mus. Nat. Hist., vol. 106, no. 1,pp. 1-89.1958. Nev^' distribution records of North American Trox (Coleoptera:Scarabaeidae). Coleopterist's Bull., vol. 12, pp. 43-46.1962. A revision of the genus Trox in South America (Coleoptera:Scarabaeidae). Bull. Amer. Mus. Nat. Hist., vol. 124, pp. 105-167.Waterhouse, G. R.1836. VL Descriptions of the larvae and pupae of various species ofcoleopterous insects. Trans. Ent. Soc. London, vol. 1, pp. 27-33.Xambeau, V.1892. Moeurs et metamorphoses d'insectes. Ann. Soc. Linn. Lyon, vol. 39,pp. 135-185.1895. Moeurs et metamorphoses des insectes. In 6e Memoire, pp. 34-35.1896. Moeurs et metamorphoses d'insectes. Cinquieme memoire (suite).Ann. Soc. Linn. Lyon, vol. 42, pp. 53-100, vol. 43, pp. 123-188.

60 U.S. NATIONAL MUSEUM BULLETIN 2 79PC . .
Illustrations
62 U.S. NATIONAL MUSEUM BULLETIN 2 79
Figures 1-2
1. Trox unistriatus Beauvo'is. Head.
2. Trox variolatus Melsheimer. Epipharynx.
LARVAL TAXONOMY OF THE TROGINAE IN NORTH AMERICA 63
AFS
T, UNISTRIATUS
T. VARIOLATUS
PE \
MS / ^ S
64 U.S. NATIONAL MUSEUM BULLETIN 279
Figures 3-8
3. Trox scaher (Linnaeus). Epipharynx.
4. Trox sonorae LeConte. Epipharynx.
5. Trox spinulosus dentibius Robinson. Epipharynx.
6. Trox aequalis Say. Epipharynx.
7. Trox unistriatus Beauvois. Epipharynx.
8. Trox fascifer LeConte. Epipharynx.
LARVAL TAXONOMY OF THE TROGINAE IN NORTH AMERICA 65
AS ' V.? i "\ "^^^5^' ,^ .' 4V^* ?-- '' f\ V-..-' * '
T. UNISTRIATUS^A ?'' ?*
66 U.S. NATIONAL MUSEUM BULLETIN 2 79
Figures 9-15
9. Omorgus scutellaris (Say). Epipharynx.
10. Omorgus rubricans (Robinson). Dorsal aspect oflabium and hypopharynx.
11. Omorgus suberosus (Fahricins). Epipharynx,
12. Omorgus carinatus (Loomis). Dorsal aspect of labiumand hypopharynx,
13. Omorgus monachus (Herbst). Ventral aspect ofabdominal segment 8 of female pupa.
14. Omorgus monachus (Herbst). Ventral aspect ofabdominal segment 8 of male pupa.
15. Trox tuberculatus (De Geer). Egg bursters fromdorsum of mesothorax and metathorax.
LARVAL TAXONOMY OF THE TROGINAE IN NORTH AMERICA 67
140. MONACHUS T. TUBERCULATUS
68 U.S. NATIONAL MUSEUM BULLETIN 2 79
Figures 16-22
16, TroxfronteraYauriG. First stage larva.
17. Trox fronfera VauTie. Second stage larva.
18. Trox frontera Vaurie. Third stage larva.
19. Trox sordidus LeConte. Dorsal aspect of labiumand hypopharynx.20. Trox sonorae LeConte. Second and third segmentsof antenna.21. Omorgus asper LeConte. Second and third segmentsof antenna.
22. Trox sonorae LeConte. Lateral aspect of segments 7,8, 9, and 10 of abdomen.
LARVAL TAXONOMY OF THE TROGINAE IN NORTH AMERICA 69
0. ASPER T. SONORAE
70 U.S. NATIONAL MUSEUM BULLETIN 2 79
Figures 23-2823. Trox and Omorgus eggs.A. Omorgus texanus LeConte.B. Trox scaler (JAnm.c\\^).C. Trox atrox LeConte.D. Trox sonorae LeConte.E. Omorgus monachus {Yl&vh?,i).
24. Omorgus monachus (Herbst). Head.25. Ormogus texanus LeConte. Head.
26. Omorgus inflatus (Loomis). Dorsal aspect of galeaand lacinia.
27. Omorgus punctatus {GcviTidiv). Anterior aspect of leftmetathoracic leg.
28. Omorgus carinatus (Loomis). Ventral aspect of seg-ment 2 of abdomen.
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Figures 29-3429. Omorgus fuliginosus (Robinson). Lateral aspect ofthorax.30. Omorgus monachus (Herbst) . Prothoracic leg of pupa.31. Trox sonorae LeConte. Prothoracic leg of pupa.32. Omorgus monachus iYl&vh^X). Dorsal aspect of pupa.33. Omorgus monachus (Herbst). Lateral aspect ofsegments 4 and 5 of abdomen.34. Omorgus monachus i):l&vhst) . Ventral aspect of pupa.
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330. MONACHUS
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Figures 35-3935. Trox sonorae LeConte. Lateral aspect of segment 5of abdomen.36. Trox foveicollis Harold. Lateral aspect of dorsalarea of segment 2 of abdomen.37. Trox tuberculatus (De Geer). Lateral aspect of dorsalarea of segment 2 of abdomen.38. Trox atrox LeConte. Anterior aspect of leftmetathoracic leg.39. Trox robinsoni Vaurie. Lateral aspect of prothoraxand mesothorax.
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39T. ROBINSONl
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Figures 40-4940. Trox scaber (Linnaeus). Dorsal aspect of right andleft mandibles.
41. Trox scaber (Linnaeus). Dorsal aspect of leftmaxilla.42. Trox unistriatus (Beauvois). Dorsal aspect of leftmaxilla.43. Trox sonorae LeConte. Dorsal aspect of right andleft mandibles.44. Trox frontera Vaurie. Distal portion of terminalantennal segment.45. Trox sonorae LeConte. Distal portion of terminalantennal segment.46. Trox scaber (Linnaeus). Distal portion of terminalantennal segment.47. Trox spinulosus dentibius Robinson. Distal portionof terminal antennal segment.48. Omorgus scutellaris (Say). Dorsal aspect of right andleft mandibles.49. Omorgus texanus LeConte. Dorsal aspect of leftmaxilla.
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480. SCUTELLARIS \_BR
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Figures 50-5950. Omorgus scutellaris (Say.) Extruded rectal mem-brane.
51. Omorgus scutellaris (Say). Caudal aspect of lastabdominal segment (anal lobes in nonextrudedposition).52. Trox sonorae LeConte. Extruded rectal membrane.53. Trox sonorae LeConte. Caudal aspect of lastabdominal segment (anal lobes in nonextrudedposition). 54. Trox aequalis Say. Frons.55. Trox fascifer LeConte. Frons.56. Trox sonorae LeConte. Biforous spiracle.57. Omorgus fuliginosus (Robinson). Dorsal aspect oflabrum.58. Trox scaber (Linnaeus). Frons.59. Omorgus monachus (Herbst). Cribriform spiracle.
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0, MONACHUST. SCABER