DIP TER A. 
459 
eyes are contiguous in both sexes. The antennae are two- 
or three-jointed, and are furnished with a style or bristle in 
some genera, in others not. The venation of the wings 
varies greatly in the different genera. We are unable, there¬ 
fore, to point out distinctive features drawn from these 
organs. The figure given (Fig. 554) represents a single 
genus rather than the family. 
The flies are generally slow and feeble in their move¬ 
ments. In some species that feed upon flowers the pro¬ 
boscis is very long, sometimes exceeding the body in length. 
Other species take no nourishment in the adult state, and 
have no proboscis. The empodia are pulvilliform. 
“ The larvae are apparently chiefly parasitic, and in the 
few species in which they have been observed are parasitic 
on spiders or their cocoons, in the former cases the young 
larvae living within the abdomen.” (Williston.) 
Family Nemistrinid^: (Nem-is-trin'i-dae). 
The Tangle-veined Fites. 
The members of this family are of medium size; some 
of them resemble horse-flies, and others bee-flies. They 
can be recognized by the peculiar venation of the wings, 
there being an unusual amount of anastomosing of the 
veins (Fig. 555), which gives the wings a very characteristic 
appearance. 
