PROTECTIVE DEVICES 51 



FIG. 41. Pupa of interrogation butterfly on upper part of under side of branch, 

 protected by its resemblance to a fragment of leaf below it. After photograph by 

 V. L. Kellogg. 



ever collected such, and while handling it heard now 

 and then a peculiar popping sound ? These are the bom- 

 bardier beetles. (See Fig. 43.) You will soon learn to 

 know them by their bluish, blackish, or greenish bodies, 

 with head, prothorax and legs yellowish or reddish yel- 

 low. These beetles have at the hind end of the body little 

 sacs in which they secrete a volatile fluid ; so, when one 

 of these bombardier beetles is about to be overtaken by a 

 pursuing enemy, a sudden pop, and he surprises his 

 would-be captor with a report not unlike that of a little 

 popgun, and then bewilders him with a load of smoky 

 gas fired into his face. During this momentary be- 

 wilderment of his adversary, the bombardier beetle 

 makes good his escape. 



