387 



the lioloiiu'tabolic Pal<ico<H<itj<)j)tcr(i must liavo been tlio uncostors, 

 bilt tliiMi the IK'tcroinctabola must havo boon developcd polypliy- 

 lotically, aud what was always cousidered as being- primitive, 

 woiild turn out to be secondary. 



None of the different causes of huk)uiotaboly, given by the 

 other writers which I have already quoted, can be the reason 

 according- to Handlirsch, bccause many hirvae have remained 

 phytophag'ous, and nevertheless are still lieteronietabolic. Neither 

 can endophagism be the reason, because nearly all the Holometabola 

 are carnivorous or phytophagous. Heterometabola as well as Holo- 

 metabola can lead an aquatic or subterraneous life, so that only 

 meteorological causes remain. The beginning of many groiips 

 of the Holometabola at the same geological period, namely in the 

 transitory period between Palaeozoicum and Mesozoicum, also 

 indicates a heterophyletical origin. Perhaps the glacial age of the 

 Perm has been the decisive factor. Ho we ver this may be, it is 

 certain, that Handlirsch, on account of his extraordinary knowdedge 

 of fossil insects, does not thiiik that the inonophyletic origin of all 

 Holometobola is possible. Por the problem which I am endeavouring 

 to solve, this means that the skinreliefs of the larvae and nymphae 

 of the different orders need not necessarily agree with each 

 other. I will soon refer to this point again, after having compared 

 the pupa of the Lepidoptera with the caterpillar. 



PouLTON (1890, p. 193) drew attention to the fact that the pupae 

 of the Sphingidae exhibit for a short time the same pattern which 

 the caterpillars possess in the last instar. The stripes, however, are 

 secondarily bidden by a brown colour, in regard to which it sliould 

 be noticed that the wings and other new-formed parts adopt tliis 

 colour later than the organs already present in the larva. Poulton 

 did not attach much value to these stripes, for he says : "The 

 persistence of such colours depends upon the fact, that the hypo- 

 dermis-cells of larva and pupa are the same, so that any pigment 

 contained in them during larval life, may remain unchanged after 

 the pupal period has begun". 



Though I have great confidence in Poulton's knowledg-e of 



