602 
DIPTERA. 
The family as a whole includes about two hundred species; those 
recorded from India are some half-dozen species of Thereva and 
Phycus. 
Mydaim:. 
Large or very large flies. Antennae club-like, rather long, the 3rd joint 
flattened. Venation characteristic, branches of radius coalescing, and 
-first branch of media ending at or before the tip of the wing, which is 
often dark coloured. 
These flies have the general appearance of large Asilids, from which 
the above characters will be enough to distinguish them. Like the Asi¬ 
lids they are predaceous in both adult and larval stages, and the larvse 
have been found in rotten wood. They constitute a small and wide¬ 
spread family of which little is known. There is one Indian species 
belonging to the genus Leptomydas in the collection of the Indian 
Museum. The characteristic venation is shown on PL LIX. 
Asilids. 
Antennae 3-jointed, 3rd joint generally elongated, with or without a 
terminal style. Head broad, depressed between the eyes. Proboscis 
stout, sharp and horny. Body generally long, with strong bristles, 
often hairy. Legs and feet strong, pulvilli usually large, empodia 
bristle-like. Squamae rudimentary or absent. Five posterior cells, of 
which the ls£ and ith may be closed. Anal cell open or closed. 
Genital organs usually conspicuous. 
A very large family whose members are abundant in the plains, and 
may considerably benefit us by their extraordinary appetites. They 
prey upon other insects of many kinds and 
their voracity is amazing. They do not 
fly much, but may be seen lying in wait for 
their victims on twigs and stubble or leaves, 
generally near the ground, and their short 
flights produce a rather loud dull buzz. 
Prof. Poulton (Trans. Ent, Soc., 1907) has 
made a study of the food of predaceous 
insects, and has found that Asilidce prey 
chiefly on Hymenoptera, Diptera, Coleop- 
tera, and Lepidoptera, and less frequently on Orthoptera, Neuroptera, 
Homoptera and Hemiptera (in India Asilids feed extensively on Oxya 
Fig. 394— Head of an Asilid 
SHOWING DEPRESSION BET¬ 
WEEN THE EYES. 
