MEMOIES OF THE NATIOI^AL ACADEMY OF SCIENCES. 
5a 
of Lepidoptera, only the larvfe of the Trichoptera, Panorpidfe, and Tenthredinidje approaching 
tliem, they do not seem to afford salient features of value for subordinal characters. Yet there- 
are some archaic features, sucli as the arrangement of the hooks on the abdominal legs, the • 
presence of eversible coxal glands on the under side or on the sides of the body; and in the larva, 
of Eriocephala 'sve have subordinal characters in the absence of a functional spinneret, also in the 
exti’aordinai’ily large size of the antenine, and of the maxillary palpi of that genus. 
Tlie process of specialization in the larva has effected not so much the general form of the 
body as the armature of the abdominal legs and of the body. Chambers, and also Dimmock,. 
(Psyche, iii, 99, 1880) has shown in Lithocolletis and in Gracilaria, especially, the changes which 
take ])lace in the head and mouth parts as well as feet of the larva after the first molt, in adapta- 
tion from a mining to a free existence. But in free-feeding forms it is diflicult to distinguish a. 
normal Tineid larva from a Tortricid or Pyralid larva, and as yet no characters diagnostic of them 
and other families have been indicated. With the exception of the larvte of certain Tineina, of 
the Cochliopodidic (Limacodidm), of the Psychidjc, those of the Hesperians and the onisciforra 
caterpillars of Lycaenida^, leindopterous larvm are remarkably homogeneous in form, as they are- 
in habits. The only reliable larval characters for distinguishing families are the differences in the 
piliferous tubercles, the number of hairs or setrn arising from a tubercle, or the shai)e and size of 
the tubercles themselves, and even within the limits of any family there is great variation in 
these, as seen in tiie Saturniid^e, or the Ceratocampidae, or Arctiida*, etc. 
The resemblance between the larvm of the Trichoptera and the Lepidoptera is remarkably 
close, their internal and external anatomy being nearly the same, the Lepidoi^tera differing chieffy^ 
in the i)resence of abdominal legs; these, however, being absent in IVIicropteryx. 
Supposing that the Lei)idoptera did spring from some neuropterous group allied to the stem 
form of the Trichoptera, the type at once after the primitive lepidoptera ceased to live in the water, 
if its ancestors were aquatic, assumed abdominal legs, hooks developed on them, at first a pair, then 
more until two complete rows appeared, and the larva was fitted to climb the stems of plants in 
order to feed on the leaves. Eventually we may imagine that the larvae, owing to the attacks of 
insect parasites, sought shelter by mining leaves, seeds, twigs, stems, trunks, and even roots of 
plants. In adaptation to these novel surroundings, the mining fornis by disuse lost their legs, 
their bodies became flattened and otherwise modified as in certain Tineina, or the sack bearers- 
were modified in adaptation to their x^eculiar habits. This great diversity in the inode of obtain- 
ing their vegetable food and their exposure to varying surroundings resulted in manifold special 
adaptations in ornamentation and armature, hem^e the groups most successful in the struggle for 
existence became very numerous in genera and species. 
The generalized forms may be detected by the larvm having one-haired warts, with minute 
tubercles without spines, but other ]»rimitive forms have large tubercles, warts, hnm])S, or highly 
colored lines, bands, or spots. While the larval characters are useful in distinguishing genera 
or families, they do not appear to present salient subordiual characters, as they do in Coleoptera, 
Diptera, and Jlymenoptera. 
(i. The generalized pupal forms are those nearest to the inijpa libera of Trichoptera and the 
Keuroptera, etc.; such is that of ^licropteryx. Those pup:e with more or less free abdominal 
segments, the Fapw incompletw of Ghai)man, are plainly more archaic or generalized than those 
belonging to his division. Pique obtecta\ Avhich com[)rise the modern or specialized forms. Where 
the ends of the maxillary ])alpi appear externally under the eyes; where the labial palpi are 
visible; wliere Avhat we call the paraclypeal pieces are iiresent, we have survivals of the characters 
of tha 2 ? iqni libera of Microptojyx. When these features have been by modification lost, we have 
the uniform obtected x>ni)a of the Neolepidoptera, and these characters are so persistent that they 
are of high taxonomic value. 
7. The pupa, then, is of the greatest importance in defining tiie larger groups of the haustellate 
Lepidoptera, and chiefly for the reason that the lepidopterous pupa, with its so-called wing and 
appendage cases, appears to represent not only what maybe called a subimaginal condition, but a 
still earlier, lost, or extinct iinaginal type, a type perliaxis midway between the ametaboloiis and 
metabolous series. This is suggested by the wing-cases which are as m ametabolous nymphs, 
such as those of Dermaptera, Termitida*, and Psoeidie, as well as of Heiuiptera; and, as shown 
by Spuler, the venation of the lepidopterous pupa is almost identical with that of the BlattidJC; 
