INSECTS 



a perfect insect, while the immature adult cicada goes 

 over into the fully mature form quickly and without a 

 molt. 



We may conclude, therefore, that the pupa of insects 

 with complete metamorphosis corresponds with the immature 

 stage of the adult in insects with incomplete metamorphosis. 

 This idea concerning the nature of the insect pupa has 



been well expressed and 

 more fully substantiated 

 by E. Poyarkoff, and it 

 appears to have more in 

 its favor than the older 

 view that the pupa cor- 

 responds with the last 

 nymphal stage in insects 

 with incomplete meta- 

 morphosis. According 

 to Poyarkoff's theory, 

 the pupa has no phylo- 

 genetic significance, that 

 is, it does not represent 

 any free-living stage in 

 the evolution or ances- 

 tral history of insects; 

 it is simply a prolonged 

 resting period following 

 the shedding of the last 

 larval skin, which termi- 

 nates with an added 

 molt when the adult is 

 fully formed. 



It frequently happens 

 that a pupa has some 

 of the adult characters 

 better developed than 

 has the adult itself. The 

 pupae of insects that 



B 



Fig. 141. Showing the resemblance of 

 the pupa of an insect with complete 

 metamorphosis to the immature adult 

 form of an insect with incomplete meta- 

 morphosis 

 A, immature adult cicada, taken from the 

 last nymphal skin. B, immature pupa 

 of a moth, taken from the last larval 

 skin. C, the mature pupa of a wasp 



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