202 FIELD ZOOLOGY. 



they resemble the house flies in the gray tints of the body 

 and in the buzzing sound with which they fly, though the 

 buzzing is not so pronounced in the case of the house fly. 

 This fly family, Howard, the government entomologist, 

 tells us, is the most beneficial of all the fly families, and the 

 benefit conferred by them enormous. The Tachina files 

 make short work of a brood of army worms by laying 

 their eggs in the juicy bodies, and the Tachina larvas do 

 the rest. They also attack grasshoppers, saw flies and 

 saw fly larvae, bugs, beetles, and wasps by the same sure 

 parasitic means. Any big-bodied, dark-colored fly with 

 bristling, stiffish hairs, rather sparsely scattered over the 

 surface of its body, is fairly sure to be a Tachina fly, and 

 should be carefully let alone; and, if it by any chance 

 gets into the house, it should in due time be turned out of 

 doors where it may freely carry on its good work of getting 

 rid of harmful insects. 



The Syrphids are the flies that rival the Tachinas in 

 point of usefulness to man. The larvae vary in their 

 feeding habits, but most of them are useful in this stage; 

 some of them feed upon plant lice, some upon decaying 

 plant and animal remains. In the adult stage they are 

 the flower pollenators. The drone fly that comes into 

 the house in the late summer is one of these Syrphids. 

 It much resembles a bee in appearance, hence its name. 

 Its maggot is the rat-tailed larva so often found in mud 

 or excrementitious matter. They are all conspicuous 

 flies, with some bright markings on the body, usually 

 yellow; and often metallic in color, or green with black 

 bandings. 



Of these two fly families, all the members are bene- 

 ficial ; of some of the other flies mentioned in the beneficial 

 list there are some that would be rather on the "half- 



