54 
MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
and Fulgoridie. The wings of the lepidoi)terous pupa may be said to be in the nymph stage of 
the ametaboloiis insects mentioned, since they are direct outgrowths from the tergites of the 
segments from which they arise. If the wing-cases of any lepidopterous pupa, together with the 
ineso- or metathorax, are, before its larval skin is molted, removed and spread out, they bear, as 
Siguier shows, a striking resemblance to those of a beetle, Tenues, Psocus, or any ITeiuipterous 
nymph. There are no traces in the pupa of any of the isolated chitinous pieces in the membrane 
connecting the wings with the trunk, which are seen in the imago. If the wing of the immature 
imago is removed from the i)upal wing case, it will be seen to difi'er greatly in shape and venation 
from that of the pupa. The pupal venation is ancestral and phylogenetic; that of the imago is 
more sx)ecialized, showing the results of a long process of adaptation and modification. So it is 
with the api)endages; those of the maxilhe, labium, and of the legs dilfer greatly, as anyone has 
observed who has studied fresh pupie, as compared with those from which the imago is ready to 
emerge. Those of the pupa show important differences; they are not simply cases, but differ in 
structure, and possibly represent the appendages of an ametabolous ancestor, a progenitor which 
may have descended fi'om the campodeiform ancestor of the class of insects. 
The importance of the pupa is also seen wlien we comiiare those of the generalized Lepidoptera 
with the more i>rimitive generalized dipterous families Bibionidm, Cecidomyiidai, Tipulidie, 
Mycetophilidm, etc. The close resemblance between the orthoraphous Dipterous pui)a and Tineid 
pupa affords strong evidence that the two orders are not only closely allied, but even that they 
may have originated from a common ancestry, the loss of thoracic and of abdominal limbs and the 
reduction of the head and its appendages of dipterous larvre, as well as the reduction of the 
hind wings, being due to modification from disuse. In the Dipterous ])upa (Ciilex, etc.) the hiud 
pairs of wings are nearly as well developed as those of lepidopterous pupm. 
8. The imaginal features in the haustellate Lepidoptera will iu general be found to correspond 
with the pupal characters, though they are not so salient and striking as the latter after these 
have been once observed and appreciated. In the moths (Heterocera) especially, the adaptative 
characters have concealed the more fundamental or primitive characters. What we regard as 
adaptative or secondary characters are the absence of A^estiges of mandibles and of maxillary 
palpi, coupled with the great development of the maxillm theniseha^s, the usually broad freuate 
wings, and tlie difference in shape of the two pairs, besides the specialization of the scales, not 
only of the wings, but of those forming the vestiture of the legs (iu XoTctuidm, etc.), 
9. What we regard as generalized or ancestral chai'actei’s in the haustellate Lepidoptera are 
those which have proA'ed of especial service iu studying the phylogeny of the order. These are 
the retention of nouropteroid characters, such as the square head, the small eyes, the A^estigial 
mandibles; in the Eriocephalida?, the retention of the lacinia and galea, the retention of the 
maxillary piilpi; in the higher moths the elongated thorax, the large metathorax, with separate 
scuta, the exserted large male genital armature of Mici’oi>teryx and of the Psychidje, the small 
narrow wings of both pairs, and the trichopteriform A^enation of the more generalized Tineina 
and of the EriocephalidiC (Protolepidoptera); also as respects the markings of the wings, the 
absence of highly colored spots, and even of bars crossing the wings. AA’heii, as iu the highly 
colored Tineids, the wings are spotted, they are often barred, this style of markings seen in Adela, 
having been possibly handed down from or at least reminding us of certain beautifully orna- 
mented and barred trichopterous genera. 
It will be seen, then, as we pass up from the Protolepidoptera to the butterflies, that there 
has been more or less extinction of neuropteroid features and an increasing specialization of the 
parts of the thorax, of the maxilhn, of the shape of the wings, including their scales and markings 
in general, spots succeeding bands and bars, brighter and more varied markings the dull uniform 
hues of many micros and Bombyces. 
THE STEM FOR3IS OR PROGENITORS OF THE LEPIDOPTERA. 
It seems to us that in the discoA^ery of two-lobed maxillte in Eriocephala, and other anatomical 
features we have new data for discussing this subject, or at least for critisiug the Auew perhaps 
quite generally held that the Lepidoptera have directly descended from the Trichoptera or from 
forms more closely resembling them than other neuropteroid orders. 
