FLESH-FLIES THAT ATTACK LOCUSTS. 



323 



In 1869 large numbers of tlie grasshoppers were destroyed by a parasite eating their 

 vitals. It comes from an egg deposited by a blackish fly. Many have died from the 

 same cause this year. — [Jas. S. Cantwell, Smithfield, Cache County, Utah. 



On the 24th ultimo I first noticed that the 'hoppers were getting wings, and now 

 four-fifths of them are winged. A great number of them are dying from the effects of 

 a grub or maggot which devours the inside of the 'hopper, leaving but little more than 

 the shell.— [W. J. Newell, Athol, Iowa, July 2, 1877. 



There are doubtless many different species of these Tachina-flies that 

 attack our locusts, but by far the most common is the Anonymous 

 Tachina fly (T. anonyma Eiley), which attacks also a large number of 

 other insects."^^ The Yellow-tailed Tachina-fly {Uxorista fiavicauda 

 Eiley, Fig. 59), which more particularly attacks the army-worm, will 

 serve to illustrate these insects. 



Flesh-flies. — These flies also attack the locust. They greatly resem- 

 ble the preceding in general appearance, but may be distinguished by 



the style of the antennae being 

 hairy instead of smooth. Judg- 

 ing from the accounts of corre- 

 spondents, and the well-known 

 habit of breeding in dead and de- 

 composing animal matter which, 

 these flies possess, they are most 

 attracted to those locusts that are 

 feeble or already dead, and are 

 fond of laying their eggs on speci- 

 mens which have just molted, and 

 are yet pale, soft, and helpless. 



Fig. 60.— Sakcopuaga carxaria ; greatly enlarged. 

 (After Emerton.) 



Fig. 61.— Sakcophaga carnaria— p u p a - 

 rium; greatly enlarged. (After Emerton.) 



These flies lay elongate and delicate eggs, which hatch very quickly. 

 They sometimes hatch, in fact, within the oviduct, so that the fly gives 

 birth to living larvae. These are distinguished from those of the Tachina- 

 flies by being more concave and truncated at the posterior end (see 

 Fig. 62, &). The Tachina larva is rounded posteriorly, with a small spi- 

 racular cavity, easily closed, and having a smooth rim j it contracts to 

 a pupa, which is quite uniformly rounded at each end. The Sarcophaga 

 larva is more truncate behind, with fleshy warts on the rim of the spi- 

 racular cavity, and with a more tapering head ; it contracts to a pupa, 

 which is also truncate behind, and more tapering in front, where the 

 prothoracic spiracles show as they never do in Tachina. 



™ See Mo. Ent. Eepts. 4, p. 129 ; 5, p. 133. . 



