DIPT ERA. 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. 



nil 



Ij + IX Vj -t- VII, 



FIG. 554. Wing of Ewlonchus. 







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.E (Nem-is-trin'i-dae). 

 The Tangle-veined Flies. 



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. 



