127 



the holuinetabulie Paiaewlicttfoptem must have been the ancestors, 

 but then the lleterometabohi nuist have been developtnl polypliy- 

 letii^Uy, and what was always considereil as being primitive, 

 wouhi turn out to be seeondary. 



None of the different e^iuses of holometaboly, given by the 

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

 according to Haniu-irsch, because many larvae have remained 

 phytophagous, and nevertheless are still heterometabolic. Neither 

 can endophagism be the reason, because nearly all the Holometabola 

 are carnivorous or phytophagous, lleterometabola as well as Holo- 

 metabola can lead an aquatic or subterrani>ous life, so that only 

 meteorological causes remain. The beginning of many groups 

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

 transitory |>eriod between Palaeozoicum and Mesozoicum, also 

 indicates a heterophyletical origin. Perhaps the glacial age of the 

 Perm has been the decisive factor. However this may be, it is 

 certain, that Hasuliiu^c'H, on account of his extraordinary knowledge 

 of fossil insects, does not think that the monophyletic origin of all 

 Holometobola is |M>ssible. For the problem which I am endeavouring 

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

 of the different orders need not neccssjirily 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 Sphingulae exhibit for a short time the same pattern which 

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

 secondarily hidden by a brown colour, in regard to which it should 

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

 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 knowledge of 



