78 FIRST BOOK OF ZOOLOGY. 



In the summer and fall, various kinds of caterpillars are 

 seen crawling over the sidewalks and along fences. They 

 are not now searching for food, but are seeking an appro- 

 priate place where they can change into the chrysalis state. 



From the long, active, and often devastating caterpillar, 

 having three pairs of small legs in front, and other pairs of 

 blunter legs behind, the creature gradually changes into a 

 body, blunt in front, tapering behind, with no indications of 

 legs, head, or any of the appearances seen in the caterpillar, 

 except that the hinder part still shows the division of that 

 portion into rings or segments as in the caterpillar, and signs 

 of life are still manifested by this portion moving from side 

 to side, when touched. Many caterpillars spin a case or co- 

 coon, as it is called, in which it incloses itself previous to 

 changing to a chrysalis. The thread with which they make 

 this case issues from a little tube in the lower part of the 

 mouth or labium. Silk is made from the thread composing 

 the silk-worm's cocoon. 



FIG. 79. A, Hinder Portion of Chrysalis-skin hanging ; B, C, Enlarged View of Hinder End, 

 to show the little Hooks by which it hangs. 



74:. Fig. 79, Ay shows the hinder portion of a chrysalis- 

 skin, the insect having escaped from it, and the forward part 



