DIPTERA 



835 



colors. Three ocelli are present. The antennae are only three- 

 jointed and the third segment bears a style or an arista (Fig. 1073). 

 The proboscis is usually short, only a few 

 members of the family having it long like 

 the bill of a snipe. The wings are broad, 

 and when at rest are held half open. The 

 empodia are pulvilliform (Fig. 1074). 



The venation of the wings is compara- 

 tively generalized . Figure 1075 represen ts 

 the venation of a wing of the typical 

 genus. 



The flies are usually of moderate size. 

 They may be found about low bushes and 

 on tall grass. They are sometimes slug- 

 gish and, therefore, easily caught. They 

 are sometimes predacious upon other 



Fig. 1073.— 



Antenna 

 of Chryso- 

 pila. 



Fig. 1074. 



insects, and the species of Symphoromyia suck blood as do horseflies. 



The females of the genus Atherix have the remarkable habit of 

 clustering in large numbers on branches or rocks overhanging water, 

 where they deposit their eggs in common, and dying as they do so, 

 add their bodies to the common mass, which may contain thousands 



R' /?.+. 



Fig. 1075. — Wing of Rhagio. 



of individuals. Figure 1076, copied from Sharp ('99) represents a 

 European species, Atherix ibis, natural size, and a mass of dead flies, 

 much reduced. It is said that the larvae feed upon the bodies of the 

 dead mothers until the mass is loosened and falls into the water, 

 where the larvae complete their growth. Other writers state that the 

 larvae drop into the water when hatched. 



Large masses of these flies have been observed in various parts of 

 this country; and formerly, in the Far West, they were collected by 

 the Indians and used for food after being cooked. It is said that as 

 many as a hundred bushels of flies could be collected in a single day. 

 For an account of the methods of collecting the flies and of preparing 

 them for food practiced by the Indians see Aldrich ('12). 



