628 TEXT-BOOK OF ENTOMOLOGY 



The pupae of Coleoptera and of Hymenoptera, though there is, 

 apparently, no near relationship between these two orders, are much 

 alike in shape, and, as Chapman pertinently suggests, those of both 

 orders are helpless from their quiescence, and hence have resorted 

 for protection to some cocoon or cell. 



But it is quite otherwise with the pupae of Lepidoptera and Dip- 

 tera, which vary so much in adaptation to their surroundings, and 

 hence afford important taxon.om.ical and phylogenetic characters. 

 This, as regards the Lepidoptera, was almost wholly overlooked 

 until Chapman called attention to the subject, and showed that the 

 pupae had characters of their own, of the greatest service in working 

 out the classification, and hence the phylogeny, of the different lepi- 

 dopterous groups. We have, following the lead of Chapman, found 

 the most striking confirmation of his views, and applied our present 

 knowledge of pupal structures to dividing the haustellate Lepidop- 

 tera into two groups, Paleolepidoptera and Neolepidoptera. 



The pupae of the Neuroptera, Coleoptera, and Hymenoptera differ 

 structurally from the imago, in the parts of the head and thorax 

 being less differentiated. Thus in the head the limits or sutures 

 between the epicranium and clypeus, and the occiput and gula, are 

 obscurely marked, while the tergal and pleural sclerites of the 

 imago are not well differentiated until the changes occurring just 

 before the final ecdysis. 



It is easy, however, to homologize the appendages of the pupee 

 with those of the imago of all the holometabolous orders except in 

 the case of the obtected pupa of the Lepidoptera (and probably of 

 the obtected dipterous pupee), where the cephalic appendages are 

 soldered together. 



That the appendages of the lepidopterous pupa are, as generally 

 supposed, merely cases for those of the imago has been shown by 

 Poulton to be quite erroneous. He says : " If we examine a section 

 of a pupal antenna or leg (in Lepidoptera), we shall find that there 

 is no trace of the corresponding imaginal organ until shortly before 

 the emergence of the imago. In the numerous species with a long 

 pupal period, the formation of imaginal appendages within those of 

 the pupa is deferred until very late, and then takes place rapidly in 

 the lapse of a few weeks. This also strengthens the conclusion that 

 such pupal appendages are not mere cases for the parts of the imago, 

 inasmuch as these latter are only contained within them for a very 

 small proportion of the whole pupal period." On the other hand, 

 Miall and Hammond claim that there is a strong superficial contrast 

 as to the formation of the imaginal organs, between Lepidoptera 



