81 



Caterpillar of Black Swallo'u'-tail about to pupate, and the chrysalid. 



greenish color crossed by black bands on which are yellow 

 spots; just back of the head are two tubercnles or horns 

 that are projected when the creature is disturbed; these 

 horns are also capable of giving out an ott'ensive odor that 

 forms a sort of protection against insectivorous birds. The 

 larva is now ready to go into the chrysalid state and we 

 must watch it closely if we are to see the wonderful per- 

 formance. 



For this great change, it often leaves its food plant and 

 takes a position on a dead limb of a neighboring tree or 

 even on a fence rail. A tiny silken pad is firmly attached 

 to the side of its support ; this is designed to be grasped 

 by the terminal pair of legs and to form the principal 

 means of support for the chrysalid. Having anchored 

 itself firmly to this pad, the caterpillar attaches a thread 

 to one side of the limb, then reaching its head far back 



