190 



ELEMENTARY ZOOLOGY 



winged, six-legged, graceful imago of adult stage are 

 completed, and with the molting of the chitinous pupal 

 cuticle the metamorphosis or development of the insect 

 is completed. As a matter of fact many of the special 

 organs of the adult, the legs and wings, for example, 

 begin to develop as little buds or groups of cells in the 

 body of the larva, and when the larva is ready to pupate 



FlG. 54. Chrysalid (pupa) of the violet tip butterfly, Polygonia interraga- 

 tionis. From this chrysalid issues the full fledged butterfly. (Photo- 

 graph from life.) 



these imaginal wings and legs are drawn out to the 

 external surface of the body, and may be readily recog- 

 nized as they lie on the ventral surface of the pupa folded 

 and closely pressed to the body surface. In recent years 

 the study of the post-embryonic development of insects 

 with complete metamorphosis has revealed some re- 

 markable changes of the internal organs which result in 

 a nearly complete disintegration or breaking down of 



