596 
DIPTERA. 
latter often of extraordinary rotundity. Probably the only other flies 
with which they might be confused are Stratiomyids belonging to the 
division Pachygastrince (Pl. LXI, fig. 5), and from these the squamae 
and venation will distinguish them. They are never bristly, sometimes 
hairy, generally quite smooth. The life-histories are not well known, 
but the larvae seem to be parasitic in the egg-cocoons or the bodies of 
spiders. The fly’s eggs are said to be laid, not on the spider or among 
its eggs, but on grass and stems whence in some unknown fashion the 
larvae get in touch with their unwilling hosts. 
The family is quite a small one and its members are as a rule 
uncommon. Oncodes costalis, Wlk,, is recorded from India ; we have 
taken another undetermined species at Mussoorie (PL LXIII, fig. 11), 
flying about Convolvulus flowers, and at Pusa in grass and low 
herbage. 
Nemestrinid^e. 
Moderate-sized hairy flies with characteristic venation. Antennce short , 
3rd joint simple with a thin terminal jointed style. 
The peculiar venation (fig. 387) characterises this small though 
widely-spread family. About a hundred species are known, and their 
Fig. 389— Nemestrinid Wing. 
[After Williston.) 
habits are similar to those of the Bomhyliidce , i.e., they are flower-flies, 
and suck nectar. 
The life-history of one species is partly known and is very curious. 
The eggs are laid in the burrows of a boring beetle ( Anthaxia) whence 
the larvae issue in numbers and are wafted away by the wind. After 
this it would seem probable that they cling to beetles (in this case a 
Cockchafer), and are carried with them into the ground when they lay 
their eggs, subsequently feeding on the beetle-larvae which hatch. 
Exactly how they get to the beetle-larvae is not, however, known with 
any certainty (Williston). 
