^~ m 



The Tachina Flies 



season by these parasites is quite beyond computation. I have 

 seen vast armies of the army-worm, comprising unquestionably 

 millions of individuals, and have been unable to find a single 

 specimen which did not bear the characteristic eggs of a tachina 

 fly. These flies were present in such numbers that their buzzing, 

 as they flew over the army of caterpillars, could be heard at some 

 distance and the farmers were unnecessarily alarmed since they 

 conceived the idea that the flies were the parents of the cater- 

 pillars and were flying everywhere and laying their eggs in the 

 grass and wheat. As a matter of fact, one great outbreak of the 

 army-worm in northern Alabama, in the early summer of 1881, 

 was comp letely 

 frustrated by the 

 tachina flies, aided by 

 a few other parasites 

 and predatory insects. 

 They also attack 

 grasshoppers, bugs 

 and beetles, saw-flies 

 and saw-fly larvae 

 and bumblebees and 

 wasps. 



Their eggs are 

 usually white in color, 

 oval in shape and are 

 stuck by some sort of 



a gummy substance Fig. 88.— Euphorocera claripennis. 



to the Surface of the (Author's illustration.) 



insect on which the future larvae are to feed. The small white 

 eggs are frequently seen sticking to the back of some unfortunate 

 caterpillar. From the under side of each egg there hatches a little 

 maggot which bores its way through the skin of the host insect 

 and penetrates into its body, where it lives, nourishing itself upon 

 the fatty matter and lymph, until it reaches full growth, usually 

 if not always destroying before it emerges some vital organ so as 

 to cause the death of the host insect. It almost invariably issues 

 when full grown from the body of the insect attacked and trans- 

 forms at or near the surface of the ground within the last larval 

 skin, which hardens into a brown, oval puparium. Breeding is 

 rapid and there may be several generations each summer. In 



159 



