THE LIFE HISTORY OF THE INSECT 



IJ3 



their larval state. 

 They are now ready 

 to enter upon the next 

 stage of their exist- 

 ence, that of the pupa, 

 or chrysalis. This is 

 a quiet stage, in which 

 the insect takes no 

 food, and is unable 

 to move about, and 

 it needs to protect 

 itself from its various 

 enemies. Conse- 

 quently, each cater- 

 pillar spins from cer- 

 tain silk glands in 



the mouth a shroud F'G. 42.— Cocoon in Currant Leaves. 



of silken threads, sur- 

 rounding itself by an oval cocoon composed of several layers 

 of silk, the outer ones much looser than the inner, with 



the hairs of the 

 caterpillar inter- 

 mingled with 

 the silk on the 

 inside layers. 

 When this co- 

 coon is first 

 spun it is white, 

 but the caterpil- 

 lar soon colors 

 it yellow with 

 an excretion 

 from the body. 

 The caterpillars 

 generally prefer 

 some sort of 

 frame-work to 



Fig. 43.-Cocoon on Fringe-tree. ^'^'^^ their CO- 



