SlMULUDy®. 
587 
of large objects, while the closely facetted parts are of use in cases where 
more accurate discrimination is wanted for nearer objects. The larvae 
are grub-like, and have a homy head 
and jaws. They feed mostly on decay¬ 
ing matter, being often found in 
numbers in the farmyard manure ap¬ 
plied to fields, but they also sometimes 
affect a diet of fresh vegetables and 
occasionally do damage in Europe by 
eating the roots of grasses. The pupae 
are generally free but some remain in¬ 
side the old larval skin, through which 
project two branched tubes for brea¬ 
thing. The family numbers about three hundred species from all parts 
of the world. The known Indian species belong to three genera, name¬ 
ly Bibio , Plecia , and Dilophus. We havereared also of a species Aspistes 
from rotting roots of ginger. These genera are distinguished as follows : 
2nd basal cell absent, antennae with 12 joints ... As pistes. 
2nd basal cell present, 
Radius 2"branched, front tibiae spineless ... Plecia 
Radius 2-branched, front tibiae with a spine-like process 
at the tip ... ... ... Bibio 
Radius 2-branched, front tibiae with a circlet of spines. Dilophus. 
Simuliid M . 
Fig . 380— Female bibionid 
(plecia) x' 2. 
Small fat flies. Antennce - father short and tapering , with 10 joints close 
together. Eyes touching in the male. No ocelli . Thorax humped. 
Wings broad , with only the anterior veins well-developed. Legs rather 
stout , tibia not spurred. 
There is only one genus (Simulium) in this family, but this contains 
from fifty to a hundred known species which are widely distributed. In 
India they are most generally known as u Potu 55 or “ Pipsa. ” In 
Europe and America they sometimes occur in vast numbers and do great 
damage to live-stock. The females suck blood, and their attacks not 
infrequently result in the death of the victim, whose eyes, nose, and ears 
are the points to which the pest mainly directs its attention. The bite 
leaves a small purple spot like a blood-blister, and may cause consider¬ 
able irritation. In America one species (S. pecuarum) has caused much 
