52 
MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
is not well founded, since it is more probable that both Trichoptera and Lepidoptera have had a 
common parentage. On the other hand, all agree in placing the butterflies at the head of the 
series as the most specialized modern group of families. But as regards the natural sequence of 
tlie groups between these two assemblages there are wide differences of oiiiuioii. Certainly the 
division of the order into Rhopalocera and Heterocera is amateurish and artificial, as is the 
separation of the order into the divisions of ]\Iacrolei)idoptera and Microlepidoptera. 
The lU’inciples which it seems to us should be kept in view in working out the relations of the 
groups are the following: 
1. We should keep constantly in mind that a true classification of the Lepidoptera is, like 
that of any other group of organic beings, an expression of the phylogenetic develoi^ment of the 
members of the group. 
2. The mouth-parts and pai'ticularly the highly modified and specialized maxillm, being- 
diagnostic of adult Lepidoptera, as also the absence of functional mandibles, these characters, 
together with the pupal ones, are of great phylogenetic importance and of primary taxonomic 
walue in the establishment of suborders. 
3. As in the case of the Diptera, which were divided by Brauer into lyiptm'a cyelorha])lia and 
orthorhaplia^ the pupa serving for a division of the order into suborders, the larval and imagiual - 
characters agreeing with those drawn from the pupa, so the pupal characters of Lepidoptera, as 
first employed by Chai)mau, are, it seems to us, of fundamental importance in the classification 
of the order into subdivisions of suborders, i. e., of superfamilies and families. Owing to the 
adaptive characters of the imago and also of the laiwa we have hitherto been very much in the 
dark as to the most fundamental features, such as will be of permanent value in the establishment 
of the minor groups named. Yet it will be seen that in general the imagiual characters agree 
with the pupal ones. 
Thanks to the labors of Walter* on the mouth-parts of the imago of Eriocephala, and to 
Dr. T. A. Gliapmau’s^ paper on the pupte of Heterocera, a truly epoch-making one, Ave now have 
clews to the arrangement of the order which promise the most valuable results. Inspired by the 
-labors and suggestions of these two authors, I have endeavored, after studying the structure of 
Eriocephala and Micropteryx and what pupm of other forms could be collected, to work along 
the lines laid out in these papers. 
Those entomologists who disbelieve in the importance of the transformations of insects in 
•taxonomy should bear in mind the value of larval as well as pupal characters in the Trichoptera, 
-Mecoptera, Siphouaptera, Neuroptera, and Hymenoptera. As regards the Coleoptera, it is 
evident that their classification thus far as based on adult characters is quite unsatisfactory, the 
more generalized forms having been placed at the head of the order and the extremely modified 
weevils (Rhyncophora) regarded as the “lowest” group, and that Ave shall have to depend on the 
larvm for the clew which will lead to a revision based on scientific evolutional principles. In 1883^ 
the writer attempted to show that the campodea-form larva of the Meloidm and Stylopidm were the 
most generalized coleopterous larvie, that the primitive Coleoptera Avere carnivorous forms, and 
that the scavenger and phytophagous families were deriA^ed from them; the weevils and Scolytidie, 
instead of being the lowest, proving ^to be really tbo most modified and, therefore, recent groups, 
4. The older, more generalized groups of moths are much less numerous in number of species 
than the more modern and specialized groups; such are the generalized Tiueina and the Bombyces 
as compared Avith the Geometridm and Noctuidm, as well as the butterflies, this being probably 
in part due to geological extinction. 
5. While the peculiar shape of caterpillars, Avith their round heads, reduced cephalic append- 
ages, three pairs of jointed thoracic feet, and abdominal legs, not exceeding tiA^e pairs, is diagnostic 
1 Zur Morjfiiologie der ScUmetterlingsmuudtlieile, Sitzungsb. Jena. Gea. Med. tiihI Katurwissens., 1885. Beitriige 
zur Morphologic der Schnaetterlinge, Jena. Zeit., 1885, pii. 751-807. 
2 Oil some neglected points in the structure of the pupie of Heterocerons Lepidoptera and their jirohahle value 
in classification, etc. Traus. Ent. Soc. Loudon, 1893, pp. 97-119. 
^Third Report U. S. Entomological Commission, 1883, p. 299. This view has been adopted and extended by 
M. C. Houlbert, who has published a new classification of the Coleoptera. See Rapports naturel et phyiogdnie 
des Coldopteres. Bulletin des Sciences uat. de I’Association des Eleves de la Facult(S des Sciences de Paris, iv, 
.May, 1891, pp. 62-171. 
