THEREVID2E. 
601 
Therevids. 
Medium-sized bristly or hairy flies. Head broad. Eyes contiguous in the 
male. Antennas short , 3rd joint simple usually with a terminal style. 
Ocelli present. Five posterior cells , anal cell closed near the margin. 
Therevids are probably predaceous both in the larval and adult con¬ 
dition. The larvae, like those of Scenopinids, have tin appearance of 
possessing 19 segments, and in 
Europe have been found in rotten 
wood and in earth. The pupae 
are free. The adult flies, which 
are often clothed with silvery 
grey fur, may sometimes be 
seen sitting about on twigs and 
leaves apparently waiting for 
their prey after the Asilid man¬ 
ner : though a good deal like 
Asilids in appearance, they are 
rather more slender and have 
much thinner legs (fig. 392), 
while their attitude while waiting 
(for prey?) is rather different, 
the head being held higher and 
the tail depressed ; the proboscis, 
too, is not horny and prominent as in Asilidce. Nothing seems to be 
known regarding the kind of insects on which they most usually feed, 
or of the life-histories of the Indian forms. They have a fondness for 
sitting on sand, and have more than once 
been seen at Pusa watching the pits 
made by Ant-lions, possibly in order to 
secure the insects entrapped therein. 
We have observed them dancing in 
great numbers in the early morning at 
the begininng of the hot weather at Fig. 393 —Head of a Therevid, 
Pusa. The genus Phycus (PI. LXIII, 
fig. 8) is not uncommonly met with in the plains, but nothing is known 
of it, not even that it is predaceous. Unlike most Therevids it is 
smooth and not hairy. 
