Page:Insects - Their Ways and Means of Living.djvu/306



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 o the adu]t in insects with incomplete metamorphosis. This idea concerning the nature of the insect pupa has

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 flore 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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been well expressed and more fully substantiated by E. Poyarkoff, and it appears to have lnore in its fayot than the older view that the pupa cor- responds with the ]ast nymphal stage in insects with incomplete meta- morphosis. According to Poyarkoff's theory, the pupa has no phylo- genetic significance, that lS, it does hOt represent any ffee-living stage in the evolution or ances- tral history of insects; it is simply a prolonged resting period fol]owing 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 bas some of the adult characters better developed than bas the adult itselL The pupae of insects that

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