PSlLIDiE. 
629 
Diopsidje. 
Sides of the head drawn out into horn-like projections which hear the 
eyes. Front femora thickened. 
The remarkable structure of the head makes this small family very 
easy to recognise. One species (fig. 414) is commonly met with in the 
plains, sitting about on leaves in shady 
places, but as in the case of the Celyphidce, 
nothing is known of the life-history. The 
exaggerated distance between the eyes may 
very probably give the insect increased 
accuracy in judging distances, just as 
‘ ‘ prismatic ’ ’ field-glasses give an enhanced 
stereoscopic effect, owing to the outer lenses 
_ _ being at a greater distance apart than the 
Fig. 414— Diopsid (sphyrace- ® & 
phala hearseyana) x 6. eyes of the user, and this accuracy might be 
useful if the animal were predaceous ; the 
possibility that such may be its mode of life is also suggested by the 
structure of the front femora, which is similar to that seen in several 
predaceous flies. Fig. 414 represents the commonest species of N. 
India, and another species is shown on PI. LXYII, fig. 7. 
Psilid^e. 
No vihrissce. Antennae generally 
long. Lower fronto-orbital 
bristles absent. Abdomen 
rather long and thin. Legs 
rather long. Sub-costa ab¬ 
sent , 1st posterior cell not 
narrowed. No preapical 
bristle on the tibiae. 
Very little is known of this 
family, beyond the fact that 
some of the larvae live in galls 
or in the roots of plants. Only 
one Indian species is on record, 
and the flies do not appear to 
be very common, the larvae are 
