BLISTER-BEETLES. 177 



One of our most common species is black, and occurs in large 

 numbers on the flowers of the golden rod. A number of species 

 of this family are very destructive to the leaves of the potato, 

 bean, aster, rose and other plants, and one at least is decidedly in- 

 jurious to the flowers of the cultivated shad-berry. This large 

 beetle, (Pomphopoea aenea Say), called the Pear-tree Blister- 

 beetle, is also fond of the leaves of apples, (Fig. 185). 



The metamorphoses of blister-beetles are remarkable, as they 

 do not alone undergo wonderful changes in form, but the num- 

 ber of such changes is greater than usual with beetles. The 

 adult deposits a large number of yellowish eggs in the ground, 

 which hatch into very active long-legged larva?, that run about 

 in search of food consisting of the eggs of locusts and of some 

 solitary bees. Eating the eggs of locusts is a very good habit, 

 hence the blister-beetles are decidedly beneficial in their larval 

 stage, and it is a well known fact that in a year following locust 

 troubles blister-beetles become very numerous. In other cases 

 the eggs are either laid on a plant or on the ground, and similar 

 long-legged larva? are hatched, which run about the flowers until 

 a proper kind of bee comes along, to the hairy clothing of which 

 thev fasten themselves, and in this way are carried to the nest of 

 the bee, not simply stealing the ride, however, but adding injury 

 to insult, for after quitting the unsuspecting host it devours the 

 egg or young larva and later completes its own transformation, 

 meanwhile feeding upon the accumulated stores, the rightful own- 

 er of which it has killed. 



These young larva; of blister-beetles are active little creatures, 

 with long legs, prominent jaws, large heads, and are known as 

 "triungulins." 



The most common of our blister-beetles are the uniformly 

 gray Maerobasis unicoVor Kirby, (Fig. 151, Plate II), and the 

 black Epicauta pennsylvanica DeG. As a description of both is 

 given in the first annual report it is not necessary to repeat it here. 



If these insects, as well as similar ones, should become very 

 destructive, they can be killed by a thorough application of one 

 of the arsenites, adding some milk of lime to make the poison 



