OF WASHINGTON, VOLUME XVI, 1914 151
ON MNEMONICA AURICYANEA WALSINGHAM. 1
(With Plates IX-XVI)
BY AUGUST BUSCK AND ADAM BOVING, Bureau of Entomology.
Micropteryxauricyanea Walsingham, Trans. Am. Ent. Soc. Phila., p. 204, 1882.
Eriocrania auricyanea Walsingham, Entom. Record, London, x, p. 162, 1898.
Eriocephala auricyanea Dyar, List N. A. Lep. no. 6018, 1903.
Mnemonica auricyanea Meyrick, Genera Insectorum fasc. 132, p. 5, 1912.
The only published note on the biology of any American species
of the superfamily Micropterygidoidea is by Wm. D. Kearfott
(Entom. News, p. 129, 1902). He discovered the mine and the
larva of what was presumably this species in the leaves of chest-
nut, and obtained pupae, but did not succeed in rearing the imago.
One of the authors (Busck) for several years has collected and
si udied these larva? and succeeded last spring in the rearing of a
large number of the exquisite"moths. As the American literature
on this group is so scant, it is deemed worth while to give the
following notes on the life-history, and on the remarkable struc-
ture of this American species, although most of the facts have long
been known from closely allied European species.
Mnemonica auricyanea is a small (12-14 mm. alar expanse)
strongly iridescent, golden bronze moth, sprinkled with scintil-
lating, bright metallic purple scales. The entire life of this little
insect above ground, covers but a few weeks. All the rest of its
life, more than eleven months, is passed under ground confined
within its cocoon.
The imago issues in April and lays its eggs singly on the open-
ing leaves of the Cupuliferse, (chestnut, oak and chinquapin).
In May the larva makes a large, bulgy blotch mine in the leaf.
It feeds up rapidly, within a week or ten days, falls to the ground
:md burrows down into the soil to a remarkable depth in propor-
tion to the size of the insect, sometimes as deep as a foot.' It
spins a small, very tough, oval cocoon of silk, within which it
]( 'mains curled up as a larva during the summer and fall. During
the winter the larva transforms into a most remarkable pupa,
which possesses long, arm-like, toothed, movable mandibles, with
which it cuts the tough cocoon in early spring and with which it
digs its way like a mole up to the surface of the ground, where the
imago issues.
The egg is rather large, oblong, 0.5 mm. by 0.2 mm., soft, white,
finely sculptured with minute dots. The female has a short,
horny ovipositor and inserts the eggs singly into the young leaf
near the edge, generally on the outer half. Dissection of the
1 Presented at meeting of April 2, 1914.
152 PROCEEDINGS ENTOMOLOGICAL SOCIETY
female abdomen shows that the number of eggs laid by a single
female is about forty.
The mine, (figs. 38-39), begins as a narrow line which runs out
towards the edge of the leaf. This early part of the mine is nor-
mally obliterated and makes a fissure in the leaf as this grows.
This fissure is a very characteristic feature of infested leaves.
After this short linear part the mine broadens out into a large
bulgy blotch, which always runs out to the edge of the leaf, and
normally involves the tip or one or more of the lobes. The mine
is suggestive of a beetle or a sawfly mine. The entire parenchyma
of the leaf is eaten out and the mine is equally visible from both
sides of the leaf. It is semi-transparent, so as to show plainly
the larva and the black frass, which is voided in long, irregularly
curled threads, lying loosely within the mine.
The full grown larva (fig. 1), is 9-10 mm. long, apodal, whitish
in color, somewhat flattened. Head small, flat, horizontal, light
yellow with dark brown trophi. Thoracic segments large and
bulging, first segment with lightly chitinized but rather strongly
pigmented, dark brown thoracic shield and sternal plate. Abdom-
inal segments evenly tapering to the last joint. The skin is sha-
greened, due to numerous minute, closely set, spine-like projec-
tions (fig. 3), all directed backward and probably used in the
locomotion. One pair of thoracic and eight pairs of abdominal
spiracles.
In the head (figs. 6-7), the two halves of the epicranium are
dorsally strongly prolonged backwards, separated by the very
deep upper portion of the occipital foramen; ventrally also they
are prolonged backwards, but only half as far as on the upper
side. Ventrally on the inner margin of each side of the epicran-
ium is a large triangular piece, the hypostoma, 1 which supports
the transverse bridge-shaped part of the tentorium.
On the upper side of the epicranium is found one long anterior
seta, three minute setae and several sensorial punctures, some-
what asymmetrically arranged. On the under side are found one
large and five small seta?. No true ocelli, but only a large, strongly
pigmented, ventral eyespot on each side near the antennal base.
The front2 is nearly triangular, but the converging edges do not
quite meet posteriorly at the occipital foramen. These edges are
strongly chitinized and interiorly developed into the endoskeletal
frontal ridges. The front contains two pairs of sensorial punc-
tures but bears no setae.
1 This is probably the post-gena of Kellogg. Kansas Univ. Quarterly, vol.
n, p. 53, 1894.
2 We employ this term which was first used by Lyonet, (Traite anatomiquc
de la chenille qui ronge le bois de saule, p. 34, 1762), and which has been
adopted by \Vm. T. T. Forbes, (A Structural Study of Some Caterpillars,
Ann. Ent. Soc. America, vol. in, p. 96, 1910).
OF WASHINGTON, VOLUME XVI, 1914 153
From the posterior end of the front runs on each side a curved
translucent line to the outside of the antennal base, limiting a
large, triangular area which may be homologous to the so-called
adfront of Forbes; each of these areas contains two small setae
posteriorly.
The epistoma 1 is well developed and bears two pairs of minute
setae.
The epistoma is connected with the labrum by a large soft-
skinned part, the post-labrum of Lyonet, (the "clypeus" or "an-
teclypeus" of Packard, Sharp and others).2
The labrum (fig. 4) is large and well chitinized, bilobed, the
anterior edge rounded and slightly emarginate; on the upper side
it bears one central pair of strong setae and along the edge five
pairs of smaller setae. On the under side of labrum and slightly
projecting in front of it, is the fleshy epipharynx (fig. 5) armed
along the anterior margin with a series of spines and bearing on
each side a large tuft of long hairs. It also has a pair of sensory
pits, and two pairs of small, symmetrically arranged, elongate,
elliptical, chitinous plates,
3 the proximal ones with a little tooth.
The margin of the epipharynx is strengthened by lateral rod-
shaped sclerites.
The antennae (fig. 11), are short, three-jointed;4 the basal joint
is large, membranous, without spines. The second joint is well
developed and well chitinized. It bears two large spines and two
sensory processes. The third joint is much smaller and bears one
seta and two sensory processes, the larger one of which is slightly
chitinized around its base.
The mandibles (fig. 10), are strong and placed horizontally.
They have three, large, pointed teeth, and a fourth, small rudi-
mentary tooth, indicated only on the ventral side. The large,
bluntly terminating cutting edge is separated from the teeth by
a small incision. The outer edge bears two strong seise, the api-
cal one of which is on the base of the fourth rudimentary tooth.
At the base of the cutting edge is a bunch of long branched hairs.
1 Epistoma is the chitinized marginal area between the two processes
on which the fossse of the mandibles articulate. This part Forbes calls
"clypeus," (I.e. p. 96, footnote), on the supposition "that this name agrees
better with its homology in other orders."
2 Forbes does not give it any name at all, and applies, as mentioned, the
term "clypeus" to the epistoma.
3 Compare the similar structure in Coleopterous larva; mentioned by
Geo. H. Carpenter and Mabel C. MacDowell in, "TheMouthparts of Some
Beetle Larvae, WithEspecial Reference toTheMaxilluloe and Hypopharynx,"
The Quarterly Journal of Microscopical Science, vol. 57, 1912, pp. 373-393,
figs. 10, 191, 24, and 25.
4 We accept with reservations, Trscgaardh's interpretations, (in his val-
uable paper, Arkiv. for zoologi, vol. 8, 1913. Stockholm). Possibly his
first joint is but a basal membrane and the terminal sensory process a true
joint.
154 PROCEEDINGS ENTOMOLOGICAL SOCIETY
The maxillae, labium, mentum and submentum1 are inserted in
the deeply curved hypostoma.
The maxillae (figs. 8-9), are large. The cardo is separated from
the lower part of the stipes by a transverse separating line which
can be seen by a careful examination. The cardo is without any
setae but terminates basally in a more strongly chitinized part.
The stipes is large and bears one strong and one small seta. The
palpiger is free and bears a long seta. It is fused with the sub-
galea and the maxillary lobes : the flat lacinia and the more joint-like
galea.
2 The lacinia on the dorsal side is furnished with long stiff
spines and soft hairs. The maxillary palpus is two-jointed, the
basal joint having a fine transverse line and four strong spines on
the dorsal side, and the terminal joint several small sensory proc-
esses.
Along the margin towards the labium the palpiger has a rod-like
chitinization, which at the base is connected with a similar struc-
ture along the margin of the hypopharynx. From the connecting
point starts first a staff-like thickening along the stipes, second, a
similar thickening around the lateral border of the- epipharynx
and third, a free, rod-like prolongation to the carinated frontal
suture.
The labium is somewhat broader than long with two pairs of
sensory punctures; the labial stipites form an incomplete chitinous
basal ring. The labial palpi have a broad short basal joint, an
elongated, narrow second joint with a single seta and a minute
apical joint also bearing a seta. The spinneret (the fused labial
lobes) protrudes beyond the palpi and is placed ventrally, well
within the anterior margin of the labium. The mentum (fig. 9),
is large and unchitinized, at the base separated from a short sub-
mentum by a bow-shaped transverse line. It has a single pair of
sensory punctures. The submentum is also unchitinized. On
the dorsal side of the labium towards the mouth cavity, the hypo-
pharynx is provided with a series of long branched hairs. Further
down is found a chitinized plate with the rudimentary third pair
of maxillae, the socalled maxillulae (fig. 8). They are provided
with short spines and correspond exactly to homologous elements
described in the beetle larvae by Carpenter and Mabel MacDowell,
(1. c. p. 375).
The body tubercles (figs. 2-3) are only discernible by their
setae, which are themselves rather small. The arrangement
1
Forbes, (I.e. p. 96), states, "The lower lip in caterpillars is formed of
the maxillae as well as the labium," but this is a confusion of terms, as the
term labium and lower lip hitherto have been regarded as synonyms.
- This may be more correctly interpreted as the digitus laciniac figured
by Comstock in a Coleopterous maxilla, fig. 605, in his Manual, 1895. If
so, the galea is absent.
OF WASHINGTON, VOLUME XVI, 1914 155-
is primitive. Utilizing Dyar's numbers, these setae may be in-
terpreted as follows: I, II, IV, V, and VII, nearly in a line on the
posterior annulet of the segment; VI small and a little in front of
this line; III obliquely above and behind the spiracle, with a mi-
nute IIIA obliquely before the spiracle. Besides these, there are
two minute spines (x) on the dorsal half of each joint. Thoracic
legs and abdominal prolegs are wanting.
The larva is full grown about ten days after the hatching of the
egg. It then cuts a small semi-circular slit in the upper epider-
mis of the leaf, and leaves the mine, dropping to the ground,
where it at once digs down until it finds a suitable place in which
to make its cocoon. Normally this is attained within a few inches
or even less from the surface of the ground, often next to a stone.
but in the breeding jars 1 some went down six to eight inches and
there are records of even greater depths, depending presumably
upon the nature and humidity of the soil. There the larva bends
itself into a circle and pushes the soil aside to make a small firm
cell in which it then spins its oval cocoon.
The cocoon is so tight fitting around the larva and is made of
so closely woven tough silk that it is difficult to cut it open with
dissecting needles without injuring the larva within. The cocoon
is about 2 mm. by 4 mm., of whitish silk and with small grains
of earth and sand firmly incorporated in its surface. The larva
remains within this cocoon apparently unchanged during summer
and fall, and not before sometime during the winter does it trans-
form into a pupa, which also very nearly fills out the cocoon.
The pupa (figs. 19-20-21) is most extraordinary, unlike any
other Lepidopterous pupa, and reminding one much more of those
of Trichoptera. It has all appendages free and unfused and all
the body segments movable. The head especially can be moved
up and down and sideways. There is, of course, no room within
the narrow confines of the cocoon for these movements, but if a
pupa is taken out and lightly touched with a brush, it responds
with the most grotesque nodding of its head and with the swing-
ing out of the enormous mandibles in a deliberate manner. AVhile
all of the other appendages are loose, not glued together as is nor-
mal in a Lepidopterous pupa, it is mainly the head and the
mandibles and abdominal segments, which are movable and which
1 Common large flower pots were used. These were filled with clean
sand and sifted soil, liberally mixed with small pieces of rock, and the
mined leaves were laid on top thereof. As soon as the larva? had left the
leaves, these were taken away, The pots were then buried flush with the
ground, inside an unheated breeding house, where they were sheltered from
sun and rain, but still exposed to nearly outdoor temperature during the
winter. The pots were watered half a dozen times from May to the follow-
ing January, and were then placed within breeding cases for the emergence
of the moths.
156 PROCEEDINGS ENTOMOLOGICAL SOCIETY
are utilized in locomotion, when the pupa digs up through the
earth. The legs are rather feeble and immovable and are not
used for this purpose as has been asserted. 1
The pupal skin is very thin and transparent, so that the imagi-
nal hairs and scales, as well as the eyes and ocelli can be plainly
seen through it. The only part of the pupa which is strongly
chitinized, besides the large mandibles, is the supporting mouth-
frame (figs. 14-18) formed by epistoma, pleurostoma and hypos-
toma.
From the front projects downwardly a large, peculiar, beak-
like, soft process, reaching above and beyond the base of the
labrum. On the upper part of the front are two pairs of long,
curved, stiff hairs, the same which persist on the head of most
Lepidopterous pupae (fig. 16).
The eyes are large. The antennae are free throughout their
entire length and run in a broad curve over the base of the wings
and rest on the costal edge of the wings, reaching nearly to their
tips. The first joint is large and elongate, four times as long as
the succeeding joints. The tufts of hairs on the imaginal joints
are plainly visible through the pupal sheath.
The labrum is large, subquadrate, with incurved front margin.
It is rather firm and bears six pairs of long stiff bristles.
The most conspicuous of the mouth parts are the very long,
stout, curved, armlike mandibles (fig. 15). These are strongly
chitinized and dark brown in color. Their fossa and condylus
are strongly developed and firmly jointed to the mouth frame.
Their inner edge is sharply serrated nearly to the end and the
apex is broadened out into a formidable club, which is abruptly
cut off with a flattened, somewhat hollow end, the edges of which
are armed with several strong teeth. They are capable of a strong-
outward swinging movement, which is used to tear the tough
cocoon and afterwards to dig up through the soil.
The mandibles are moved by strong muscles (fig. 18), identical
with the abductor and adductor mandibulse found in insects with
biting mouthparts, and the minute imaginal mandibles can be
found within their base by dissection (fig. 14). In this connection
we refer to Chapman's peculiar statement in his otherwise very
lucid account of an "Eriocranid" pupa. 2
1
Sharp, in his textbook, p. 327, 1909.
'That a Lepidopterous pupa should have jaws is remarkable enough;that they should be of such immense size proportionately to the insect and
should be functionally active seems at first sight incredible; but the still
more remarkable fact remains, that active and powerful as they are, there
are no visible means of working them, as they are pupal structures, used
only immediately before the emergence of the imago and have no corre-
sponding imaginal parts attached to them.
"The whole question, how these jaws are worked, will form an intorestin-j;
OF WASHINGTON, VOLUME XVI, 1914 157
The maxillary palpi (fig. 17), are bent upon themselves in five
sharp curves, with the last joint pointed downwards and forwards.
The two halves of the proboscis are widely separated and out-
wardly curved, with their tips nearly meeting in the middle line
forming a heart-shaped figure.
The labium and its three-jointed palpi are pointed downwards
in two straight, divergent staffs, reaching beyond the curved pro-
boscis.
The strongly angulated patagia, 1 (fig. 19), overlap the base of
the wings behind.
The legs are folded loosely along the body, the posterior tarsi
reaching beyond, and curved around the tip of the abdomen.
On the back of the pupa is a peculiar structure, the morphology
and function of which is not clear to us. It consists of an un-
paired, thin-walled, strap-like, longitudinal band (fig. 21, x), made
up of three separate appendages in prolongation of each other and
attached to the middle line of respectively the second and third
thoracic and the first abdominal segments.
Each abdominal segment bears two lateral pairs of strong stiff
spines. The spiracles are small and circular.
In early spring when the pupa is mature and ready for the
emergence of the adult, the cocoon is split open by an outward
movement of the mandibles which tears through the tough silk.
The pupa then wriggles out of the cocoon and laboriously digs up-
ward through the earth by the help of the mandibles, swung from
the exceedingly movable head and pushed on by the movements
of the abdomen. When it finally has made its way to the sur-
face, it lies immovable for some time, during which the last acts
of the transformation to adult take place. The mandibles be-
come immovable through the withdrawal of the imaginal skin and
mandibles, together with the strong muscles which remain in the
imaginal head. The pupal skin now splits open on the median
line of the first and second thoracic segments. The long-haired
head and thorax of the imago appear in the slit and the fully
developed moth issues. It at once seeks some support from which
to hang with backwardly extended wing, as is usual with freshly
emerged moths, but it is very quickly in condition for active
flight. It is interesting to note that if the cocoon is taken out of
the sand and placed on the surface for observation, as was done
research for some microanatomist. I fear my own training leaves me un-
equal to carry the matter much further. I am however, thoroughly satis-
fied on two points: first, that there are no muscles attached to these jaws,
second, that there are no imaginal jaws within them, whose movements
compel those of the pupal ones." Chapman, Trans. Knl. Soc. Lond. 1893,
pp. 255-263.
1 The patagina of Busck, by mistake.
158 PKOCEEDINGS ENTOMOLOGICAL SOCIETY
with several, the pupa has a period of rest after emergence from
the cocoon, during which the mandibles and the head work fu-
riously at the least irritation with a hair-pencil, or even without
such. This period evidently corresponds to the time it normally
takes the pupa to work its way through the soil to the surface.
Later on comes the period of immovability of the mandibles,
which fail to respond even if sharply irritated. This corresponds
to the resting period when the pupa under normal conditions has
reached the surface.
The imago has the head (fig. 22) and face strongly tufted with
long gray, brown and white hairs, which obscure the eyes and
mouthparts. The antenna? are simple, dark brown, with two
longitudinal light yellow lines throughout their length. Thorax
strongly haired, the long brown and gray hairs arranged in three
large whorled tufts, two over the patagia and one posteriorly.
Forewings elongate elliptical, thickly covered with large golden
scales, evenly interspersed with numerous single purplish blue
metallic scales: cilia light golden brown Hindwing dark golden
brown, with a purple sheen, semitransparent at base; cilia gray.
Abdomen brownish gray, in the female terminating in a short,
stout, brown, horny ovipositor. Legs dark gray sprinkled with
purple scales; posterior tibiae with long, sparse thin hairs on the
upper side and with two pairs of well developed spurs. Alar
expanse 10-13 mm. The venation is given in figures 12-13.
From the several clearly primitive characters which they pos-
sess in common, more especially in the neuration and the mode
of keeping the wings together by the so-called jugum (the clavus
of Spuler), there can be no doubt that the Eriocranidve and the
Micropterygidse represent the most ancestral group of Lepidop-
tera. This has been generally recognized by all modern Lepidop-
terists, but there has been considerable difference of opinion as to
the relative systematic value of these groups. Some authors have
considered the active biting mouth parts of the adult Microp-
terygidaB of sufficient systematic value to separate this group as a
distinct superfamily or even subclass. On the other hand, Mey-
rick regards the passage to sucking mouth parts in the Eriocrani-
da3 as a purely biological change of structure of much less system-
atic significance, and he treats the two groups as closely allied
subfamilies.
The actual presence of rudimentary but unmistakable mandi-
bles also in the Eriocranidse tends to support Meyrick's opinion of
close correlation, but his. description (Genera Insectorum), con-
tains some misstatements and omissions in the anatomy of the
head structures in the two groups. We consider that the differ-
ences both in the mouth parts and in the venation, as well as of
OF WASHINGTON, VOLUME XVI, 1914 159
the larvae, justify separate family rank for the Eriocranidae and
the Micropterygidae of which the latter are by far the more ances-
tral, as shown in the following comparison of their head structure.
The adult Micropterygid (Micropteryx ammanella Hlibner, is
used in this comparison), has true, well developed, strongly chi-
tinized, functional mandibles (fig. 35). These are in a general
way similar to those just described in the Eriocranid pupa, but
are much contracted. They have well developed fossa and con-
dylus, jointed on the mouth-frame and are moved by strong ab-
ductor and adductor muscles. Their outer end is sharply cut off
and palmate as in the Eriocranid pupa and toothed on the edges.
The upper one of the outer teeth is more pointed and larger than
the rest.
In the adult Eriocranid (Mnemonica auricyanea Walsingham)
are found by dissection similar but rudimentary and unchitinized
mandibles (figs. 27, 31, 33). These have not the palmate apex,
and the fossa and condylus are hardly discernible, while the liga-
ment connecting frhem to the mouth frame is large and cushion-
like. In the pupa these mandibles are plainly visible within the
base of the pupal mandibles (fig. 14), and they possess strongly
developed abductor and adductor muscles (fig. 31), identical with
those in the pupa. These muscles and the development within
the corresponding pupal structure definitely prove the mandibu-
lar nature of these organs. 1 The presence of true biting mandibles
in the Micropterygidse is therefore not of such fundamental im-
portance as Sharp, Tutt, and others have assigned to it, the less
so as rudimentary mandibles may be distinguished in certain
much higher Lepidoptera. 2 But the further presence of all the
1 Compare Chapman's statement, above quoted, in footnote, page 15(i-7,
which has been accepted by subsequent writers, as Sharp and Meyrick.
The former states, page 308 in his textbook, (The Cambridge Natural His-
tory, vol. vi, Insects, part n, 1899), "The opinion entertained by \Valter
that Micropteryx proper, (his 'hohere Micropteryginen,' Meyrick's 'Erio-
cranianaV) also possesses rudimentary mandibles is considered by Chap-
man, no doubt with reason, to be erroneous." Further in the same man-
ual, p. 437; "All the information we possess points to profound distinctions
between Micropteryx, (our 'Eriocranidse'), and Erioccphala, (our 'Microp-
terygidae,' Walter's 'niedere Micropteryginen') for whereas, in the former
the mandibles drop off from the pupa, so that the imago has no mandibles,
in the latter, the mandibles exist." Meyrick, in his monograph of tlm
Micropterygidae (Genera Insectorum, 912, p. 3), simply states in the diag-
nosis of his subfamily Eriocranince, "No mandibles." On the other hand,
it should be noted that Alfred Walter in his excellent work on the morphol-
ogy of the Lepidoptera, (Jenaische Zeitschrift fur Nalurwisscns., Bd. 18,
1884, neue Folge Bd. u, p. 751-807, 2 plates), has correct!}' interpreted these
structures in what he calls the "hohere Micropterygidae."
2 The weak and functionless mandibles have been recognized later by
Kellogg, (The Mouthparts of the Lepidoptera, Am. Nat. vol. 29, p. 546,
1895), by Packard, (On a new Classification of the Lepidoptera, Am. Natur.
160 PROCEEDINGS ENTOMOLOGICAL SOCIETY
other trophi also identical with those found in insects with biting
mouth parts, and even maxillulse lobes on hypopharynx (fig. 37),
proves the Micropterygidse a much more ancient group than the
Eriocranidse, which possess none of these characteristics but has
a true sucking mouth.
In the Micropterygidse the maxillae consist of a well developed
cardo and stipes (figs. 36-37), a palpiger which carries the six-
jointed palpus, and a subgalea which carries a distinct, well chiti-
nized lacinia with a few setae, and a two-jointed galea, the basal
joint of which is short and well chitinized, while the terminal
joint is soft and leaf-shaped, with a longitudinal series of seise.
The Eriocranidse (figs. 29-30), also possess distinct cardo and
stipes, as well as a six-jointed palpus, and the galea is also two-
jointed, but they lack altogether the lacinia, and the terminal
joint of the galea is developed into one of the hollow sheaths of a
true proboscis, is curved, has the typical serrations (figs. 25-26),
which serve to connect it with the other half of the proboscis,
and has the usual parallel ring structure and surface cilia placed
in transverse lines.
Both the Micropterygidse and the Eriocranidse possess a labium
with a well developed, three-jointed palpus, the apical joint with
the usual sensitive groove, 1 represented merely by a depression
containing the rows of sensitive cones. But in tlie Microptery-
gidse is found a setae-bearing lobe, corresponding to the galea of
the maxillae, issuing from the so-called basal joint of the palpus,
which should rather be interpreted as stipes labii. Of this setae-
bearing lobe there is no vestige in the Eriocranidse. Finally,
only the Micropterygidse, as already mentioned possess the two
maxillulae lobes, lateral to the hypopharynx. 2
The authors are under great obligations to their friend Rev. -I.
DeGryse, for the several excellent figures (1, 2, 3, 4, '5, 6, 7, S.
9, 10, 11, 15, 19, and 21), of the larval and pupal structures, which
he has studied most diligently and carefully, thus contributing
very considerably to the value of this paper.
The other figures, except the venation, were drawn by Adam
Boving.
vol. 29, p. 636, 1895) and by Francis X.Williams, (A New Eriocrania from
the Pacific Coast, Ent. News, p. 14, 1908).
1 Pointed out by O. Von Rath: Zool. Anzeiger 1887, p. 627; Zeitschrift
f. Wissench. Zoolpgie, Bd. 46, 1888.
2 These investigations of the maxillary, labial, and maxillulary struc-
tures fully substantiate the writings of Dr. Walter, who has already pointed
out most of the above mentioned characters in his excellent paper. In the
middle of the hypopharynx is plainly seen in our slides, both of the Microp-
terygidse and the Eriocranidse, the opening of the salivary glands, which
\\ alter was not able to discern on account of the condition of his material.
OF WASHINGTON, VOLUME XVI, 1914 161
EXPLANATION" OF PLATES.
PLATE IX. Mnemonica auricyanea Walsingham, larva.
Fig. 1, lateral view of full grown larva.
Fig. 2, lateral view of flattened larval skin; SP, thoracic spiracle; sp, ab-
dominal spiracles.
Fig. 3, details of the sixth abdominal segment, lateral view; .r, small un-
numbered setse.
PLATE X. Mnemonica auricyanea Walsingham, larva.
Fig. 4, dorsal view of epipharynx, labrum and post-labrum; ex, epiphar-
ynx; Ir, labrum; pi, post-labrum; mb, median bristles.
Fig. 5, ventral view of epipharynx; ch, hairtuft; ep ext, exterior epipha-
ryngeal plate ; ep int, interior epipharyngeal plate ; er, rod along the margin ;
es, sensory puncture; ex, epipharynx.^
Fig. 6, dorsal view of head, a, (on detail A), dorsal mandibular articula-
tion; af, adfront; afl, -adfrental line; an, annulus around the antennal base:
r, (on detail A), carinated lateral margin of front; e, (on detail A), epistoma;
cpc, epicranium; /, front; of, occipital foramen; pi, post-labrum.
Fig. 7, ventral view of head; epc, epicranium; h, hypostoma with /, im-
pression where tentorium is attached; m, mentum; ocl, eyespot.
PLATE XI. Mnemonica auricyanea Walsingham, larva and wing venation
of the imago.
Fig. 8, maxillse, hypopharynx and maxillulac; bb, branched bristles; r/.s,
duct of salivary glands; epc, margin of epicranium; g, galea or digitus la-
cinia; hr, chitinous rod of hypopharynx; hx, hypopharynx; I, lacinia; tup,
basal joint of maxillary palpus; mxl, maxilluke; spr, spinneret.
Fig. 9, ventral view of maxilla? and labium; cr, cardo; err, chitinization
along inner edge of cardo; Ip, basal joint of labial palpus; 1st, labial stipes;
m, mentum; mpl, basal joint of maxillary palpus; mpll, terminal joint;
ply, palpiger; sm, submentum; r, chitinous rod along the inner margin of
lacinia; st, maxillary stipes; str, chitinous rod along the margin of maxil-
lary stipes.
Fig. 10, left mandible, ventral view.
Fig. 11, dorsal view of right antenna; an, annulus around antennal base;
at, large papilla or terminal joint.
Fig. 12, venation of forewing.
Fig. 13, venation of hindwing.
PLATE XII. Mnemonica auricyanea Walsingham, pupa.
Fig. 14, labrum and mandibles of the imago within the labrum and man-
dibles of the pupa; labrum and mandibles of the pupa indicated with dotted
lines; mf, mouthframe.
Fig. 15, ventral view of left mandible.
Fig. 16, dorsal view of head; ant, antenna; /s, frontal seta-; //;, labial pal-
pus; h, labrum; md, mandible; mf, mouth frame; >n/>, maxillary palpus: />/:,
beaklike prolongation of front; pr, proboscis.
Fig. 17, ventral view of head; epc, epicranium; /;, hypostoma; //>, labial
162 PROCEEDINGS ENTOMOLOGICAL SOCIETY
palpus; m, mentum; md, mandible; mp, maxillary palpus; ofI, anterior part
of occipital foramen; ofII, posterior part of occipital foramen; oc, compound
eye; pr, half part of proboscis; SHI, submentum; tb, bridge of tentorium;
si, stipes.
Fig. 18, mouth frame and mandible with musculature, dorsal view; ab,
abductor muscle of mandible
; ad, adductor muscle of mandible ; d, dorsal
process of mouth frame on which fossa of the mandible articulates; mf,
mouth frame; t, tendon; v, ventral socket of mouth frame on which condy-
lus of mandible articulates.
PLATE XIII. Mnemonica auricyanea Walsingham, pupa.
Fig. 19, lateral view; pt, patagium.
Fig. 20, ventral view.
Fig. 21, dorsal view; x, thin-walled dorsal appendices.
PLATE XIV. Mnemonica auricyanea Walsingham, imago.
Fig. 22, lateral view of head; ant, antenna; e, epistoma; epc, epicranium;
/, front; Ip, labial palpus; I, labrum; md, mandible; mf, mouth frame;
mp, maxillary palpus; ocl, ocellus; pi, post-labrum; pr, proboscis.
Fig. 23, epipharynx and hypopharynx; mm, membrane of mouth; ex, epi-
pharynx; hx, hypopharynx; pap, sensory papilla; ph, pharynx; sc, scales;
w, sensory wart.
Fig. 24, dorsal view of head; an, antennal ring; epc, epicranium;/, front;
oc, compound eye; ocl, simple eye; ha, hair-bearing area.
Fig. 25, apex of right half of proboscis from inner side.
Fig. 26, base of right half of proboscis from inner side; ci, cilia belonging
to the external parallel series; fri, stiff connecting fringes of ventral mar-
gin; th, transverse ring-structure.
Fig. 27, ventral view of head; ex, epipharynx; h, hypostoma; hx, hypo-
pharynx; m, attachment of mentum; md, mandible; mx, attachment of
maxilla; ofI, anterior portion of occipital foramen; ofII, posterior portion
of occipital foramen; tb, bridge of tentorium; v, ventral mandibular articu-
lation.
Fig. 28, ventral side of labium; Ip, labial palpus; m, mentum; VR, organ
discovered by Von Rath.
Fig. 29, buccal surface of left maxilla; c, cardo; gl, basal joint of galea;
gll, terminal joint of galea developed as left half of proboscis; h, hypo-
stoma; mp, maxillary palpus; pig, palpiger; sgl, subgalea.
Fig. 30, ventral side of right maxilla; c, cardo; gl, basal joint of galea;
gll, terminal joint of galea; mp, maxillary palpus; pig, palpiger; sg, sub-
galea; si, stipes.
PLATE XV. Mnemonica auricyanea Walsingham, imago, figs. 31-33.
Fig. 31, ventral view of right mandible; ab, abductor muscle; ad, adduc-
tor muscle; t, tendon.
Fig. 32, frontal view of head; ant, antenna; epc, epicranium; e, epistoma;
/, front; Ir, labrum; Ip, labial palpus; m, mentum; md, mandible; mp, max-
illary palpus; pi, post-labrum; pig, palpiger; pr, proboscis (= terminal
joint of galea); sm, submentum.
PROC. ENT. SOC. WASH., VOL. XVI. PLATE IX.
PLATE X. PROC. ENT. SOC. WASH., VOL. XVI.
a
(C
PROC. ENT. SOC. WA>H., VOL. XVI. PLAT XI.
PL VTE XII. PROC. ENT. SOC. \VASH., VOL. XVI.
TIG
Fic. 16
FIG 17 18
PROC. ENT. SOC. WASH., VOL. XVI. PLATK XIII.
CS
d
c
a
(N
c5
(C
a
(C
PLATE XIV. PROC. EXT. SOC. WASH., VOL. XVI.
-epc
--Ip
mm;'
FIG 23
ha
Tic. 2'
FIG 2.6
Fie. 2.4
TIG 27
FIG, 2.9
PROC. EXT. SOC. WASH., VOL. XVI. PLATE XV
epc
3 3
-HPB
ta
N>cl
34 TIG 35
am-'
FIG 36 FIG. 37
PLATE XVI. PROC. ENT. SOC. WASH., VOL. XVI.
38.
Fig. 39.
OF WASHINGTON, VOLUME XVI, 1914 163
Fig. 33, interior view of a piece of the head of a dry specimen; ad, adduc-
tor mandibuli; epc, epicranium; md, mandible; /, tendon; ap, process to
which antenna? muscles are attached.
Micropteryx ammanella Hiiber, imago, figs. 34-37.
Fig. 34, dorsal view of head; ant, antenna; epc, epicranium; ha, hair-
bearing area; Ir, labrum, md, mandible; ocl, ocellus; pg, pilifer; pi, post-
labrum; ta, spot indicating the interior attachment of tentorial arm.
Fig. 35, upper portion of head from inner side; an, antennal ring; ex,
epipharynx; md, mandible; ocl, ocellus; pg, pilifer; ph, pharynx; r, endo-
skeletal rod; I, tendon of mandible; la, tentorial arm.
Fig. 36, ventral view of head; c, cardo; epc, epicranium; g, galea; h, hy-
postoma; /, lacinia; II, labial lobe; 1st, labial stipes; m, mentum; mp, max-
illary palpus; pig, palpiger; s<7, subgalea; sm, submentum; st, stipes; tb,
tentorial bridge.
Fig. 37, lower portion of head from inner side; epc, epicranium; g, galea;
hx, hypopharynx; I, lacinia; II, labial lobe; mxl, maxillula; Ip, labial pal-
pus; r, endoskeletal rod; sg, subgalea; t, tendon of mandible; ta, tentorial
arm; tb, tentorial bridge.
PLATE XVI. Mnemonica auricyanea Walsingham.
Fig. 38, young mine and egg puncture in chestnut leaf.
Fig. 39, old mines.
AQUATIC BEETLES, ESPECIALLY HYDROSCAPHA, IN HOT
SPRINGS, IN ARIZONA. 1
BY E. A. SCHWARZ, Bureau of Entomology.
In 1891 on the occasion of the meeting of the A. A. A. S. at
Washington, D. C., I prepared for publication a letter just received
from our lamented friend and former president of this Society,
Mr. H. G. Hubbard, relating to insect life in the hot springs of
the Yellowstone National Park. This letter has been published
in the Canad. Ent., vol. 23, pp. 226-230. At the same time I
made myself a little acquainted with the literature on insect life
in hot water and found that in America there is only one paper
referring to this subject, namely by Dr. A. S. Packard, published
in the American Naturalist on a Stratiomyid (Diptera) larva
found in Wyoming. (This same paper is mentioned by Dr.
Sharp in the Cambridge Nat. History.) In this instance the
Dipterous larva was found in hot water estimated only 20 or
30 below the boiling point. In the case of Mr. Hubbard's obser-
vations in the Yellowstone Park he expresses his regrets at not
.
* Presented at meeting of April 2, 1914.