Blister-beetles 



DESCRIPTION AND LIFE HISTORY 



The blister-beetles are especially interesting because of the feeding 

 habits of their larvae and because of the fact that they pass through more 

 stages in the course of their development than any of the other beetles 

 discussed in this Bulletin. There are six stages, the egg, three larval, 

 the pupal and the adult. 



Mention has already been made of the fact that the larvae of some 

 species feed upon grasshopper eggs. The seasonal history of these may 

 be summarized as follows: 



The Egg 



The eggs, which are small and oval in form, are very delicate. They 

 are deposited in loose clusters in holes in the ground which have been 

 excavated by the female blister-beetle. After the eggs are laid they are 

 covered with loose soil which the beetle scratches over them with her feet. 



The places chosen for egg laying are just those warm sunny spots 

 chosen by the female grasshopper for the same purpose. Thus we see 

 that the newly hatched blister-beetle finds an abundance of food close 

 at hand when it emerges from the egg. 



The First Larval Stage 



When the larva escapes from the egg its head is large and the jaws 

 are well developed. Its legs are comparatively long and the body slender. 



As soon as the body walls become hardened by exposure to the air 

 the active larva starts in search of a grasshopper egg-pod. When one is 

 found the larva gnaws its way into it and begins feeding upon the eggs. 



At the end of its first meal of uncooked omelet, which may last for 

 three or four days, the larva spends the next few days resting, and about 

 the eighth day after beginning to feed the first molt takes place and the 

 second larval stage begins. 



The Second Larval Stage 



In this stage the body is much more robust and the legs are much 

 shorter than before. After feeding for about a week another molt takes 

 place. 



The legs and mouth are now rudimentary and the body resembles 

 that of the white grub. 



After about six or seven days the skin is once more shed and what is 

 known as the ultimate stage of the second larva is begun. In this stage 

 the larva feeds more voraciously. 



After a week of almost continuous feasting the larva leaves the re- 

 mains of its repast and burrows a short distance into the soil, where a 

 smooth cell is formed. 



Within this cell another change takes place. About the third or 

 fourth day the skin splits over the head and is gradually worked backward 

 but is not entirely shed. The mouth and legs are now quite rudimentary, 

 being represented by small tubercles. The skin becomes quite rigid and 

 takes on an orange yellow color (Fig. 12, Plate VII, Page 23). This is 

 the pseudopupa or coarctate larva. 



The winter is spent in this form. In the spring the hard coarctate 

 larval skin is cast off and the third larval form appears. 



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