rilE Bl^TTERFLY 



31 



by jumps. From one molt until the next constitutes a stage 

 in the caterpillar's development, and most caterpillars pass 

 through several of these stages. In the last stage the caterpillar 

 ceases to feed and wanders about until, having reached a suit- 

 able locality, it molts for the last time. It is now shorter 

 and stouter and is 

 covered with a 

 much thicker cutic- 

 ula, and in this 

 stage remains mo- 

 tionless for a long 

 time. In this ap- 

 parently quiescent 

 stage the future 

 butterfly is known 

 as the pupa. Some 

 caterpillars spin a 

 web of silk al)out 

 themselves known 

 as the cocoon 

 (Figs. 34, 35). The 

 cocoon is attached 

 to some object 

 above ground. Others pupate above ground, protected only 

 bjr a thick cuticula, while still others pupate under ground 

 in a sort of cell which in some species is hned with silk or silk 

 mixed with the hairs of the caterpillar. 



The inactivity of the pupa is only apparent. Inside the 

 cuticula, development is proceeding rapidly, leading to a 

 very fundamental change of form. From the back of the 

 animal there grow out wings, and from its head antennae and 



Fig. .34. — Cocoon. 



