XXII. Family THEREVIDiE. 



Fig. 79. Thereva senex, enlarged. After Lugger. 



Rather small or moderate sized, elongate (American 

 forms), bristly, sometimes pilose, predaceous flies. Eyes 

 of the male contiguous or approximated; front in the 

 female not excavated. Antennae composed of three 

 joints, the third simple, with a terminal style, sometimes 

 wanting. Proboscis projecting, the labella broad; palpi 

 two-jointed. Ocelli present. Abdomen elongate, geni- 

 talia moderately or but little prominent. Legs with bris- 

 tles; empodia wanting; pulvilli rarely wanting. Third 

 longitudinal vein of the wings furcate, the posterior 

 branch terminating beyond the tip of the wing; five pos- 

 terior cells, anal cell usually closed toward the margin 



of the wing. 



205 



