606 
DIPTERA. 
etc. They are probably predaceous and are described as cylin¬ 
drical, amphipneustic with a prominence below the posterior pair of 
spiracles. The pupae are free. In the plains, as mentioned above, 
the species seem to be few in number, though individuals (especially 
Tachydromince) are often common, but they occur in fair abundance 
in the hills. This may be due to the lack of shade and moisture in 
the plains not suiting them, for in England they are found most 
often in rather damp places, such as meadows bordering on running 
brooks or in shady woods. They are sometimes rather difficult to 
identify, owing to their considerable variety of form and venation. 
Van der Wulp lists one species of each of the genera Hilara, 
Pterospilus . and Hybos as Indian. Species of the latter genus are 
quite common in the hills and can be recognised from the exaggerated 
development of the hind legs (fig. 398). 
Dolichopodim:. 
Small slim flies , generally of metallic colours , 
with long thin legs. Antennce often 
apparently 2-jointed. Proboscis short 
and fleshy. No squamae. No cross-vein 
between discal and 2nd basal cells. Male 
genital organs frequently conspicuous. 
These beautiful little flies are found as a 
rule in moist leafy places, and in the rains 
may commonly be seen on hedges, garden- 
bushes, etc., flying nimbly about and sett¬ 
ling on the leaves ; they are often easily re¬ 
cognised by their elegant form and bright 
metallic green colour (Pl. LXIII, fig. 9). 
The first two joints of the antennae are 
usually quite short, the second being some¬ 
times too small to be noticeable, and the 
third is generally oval, but in some genera 
is much elongated. It bears a dorsal or 
terminal arista. The wings in several genera are clouded or have 
dark markings. The thorax is flattened from side to side, and has 
regular rows of bristles along the back. In keeping with the dandified 
