BLISTER-BEETLES 



305 



which it left the egg-pod but is somewhat smaHer and peler. 

 After moving about in the soil for a few days, it transforms 

 to a pupa. The pupal stage lasts about two weeks. There 

 is only one brood annually, at least in Illinois and Missouri. 

 The striped blister-beetle is a striking instance of an insect 

 that is beneficial in one stage of its development and highly 

 destructive in another. 



References 



Riley, Trans. Acad. Sei. St. Louis, 3, pp. 544-562. 1878. 

 Iowa Agr. Exp. Sta. Bull. 155, pp. 377-380. 1915. 



The Margined B lister-Beetle 



Epicauta niarginata Fabricius 



This blister-beetle (Fig. 185) is a little over | inch in length, 

 black, with the head and sides of the thorax ashy gray. The 

 wing-covers are black, the inner and 

 the outer margin with a narrow 

 stripe of gray. This beetle is dis- 

 tributed throughout the eastern 

 United States and occurs sparingly 

 in Canada. The larva has been 

 found feeding on the eggs of the 

 differential locust. The first stage 

 larva is about tu inch in length and 

 similar to that of the striped blister- 

 beetle. 



The beetles are found from June 

 to October. They feed in colonies. 

 They have a special fondness for 

 beet, but also attack bean, potato, tomato, cabbage, pumpkin, 

 clematis, aster, pigweed, ground cherry and wild sunflower. 



Fig. 185. — The margined 

 blister-beetle (X 2f). 



