RILEY LARVAL HABITS OF BLISTER-BEETLES. 553 



prey must be industriously sought, they display great power of 

 endurance, and will survive for a fortnight without food in a 

 moderate temperature. Yet in the search for locust eggs many 

 are, without doubt, doomed to perish, and only the more fortu- 

 nate succeed in finding appropriate diet. Upon the slightest 

 disturbance they curl up in a ball with the head bent pretty close- 

 ly on the breast. 



Reaching a locust egg-pod, our triungulin, by chance, or 

 instinct, or both combined, commences to burrow through the 

 mucous neck, or covering, and makes its first repast thereon. If 

 it has been long in the search, and its jaws are well hardened, it 

 makes quick work through this porous and cellular matter, and 

 at once gnaws away at an egg, first devouring a portion of the 

 shell, and then, in the course of two or three days, sucking up 

 the contents. Should two or more triungulins enter the same 

 egg-pod, a deadly conflict sooner or later ensues until one alone 

 remains the victorious possessor. By the time the contents of an 

 egg are consumed, the body of the parasite has perceptibly in- 

 creased so that the white sutures between the segmental plates 

 show conspicuously, especially as there is a tendency on the part 

 of the animal to curve its body, and bring the sutures more into 

 relief. A second egg is attacked and more or less completely 

 exhausted of its contents, when a period of rest ensues, the triun- 

 gulin skin splits along the back and there issues the Second Larva 

 (PI. V., Fig. 4) — white, soft, with reduced legs and quite differ- 

 ent in general appearance from the first. This molt is experi- 

 enced about the eighth day from the first taking of nourishment. 

 The animal now naturally lies in a curved position (PI. V., Fig. 

 4, d), but, if extracted from the egg-pod, will stretch itself and 

 move with great activity, reminding one very strongly of many 

 Carabid larvae, for which reason I would designate this as the 

 Carabidoid stage of the second larva. After feeding for about 

 another week, a second molt takes place, the skin, as before, split- 

 ting along the back and the new larva hunching out of it until 

 the extremities are brought together and released almost simulta- 

 neously. This kind of molting, which is characteristic of our 

 blister-beetles up to the pseudo-pupal state, is exceptional among 

 insects, the skin being ordinarily worked backward from the head. 

 The modification at this molt is slight. The mouth-parts and legs 



