DIPTERA. — 285 
seta of the same organs which is short, thick, slightly silky, cylin- 
drical, and divided into three joints, the last of which is somewhat 
the longest. The palette almost forms a reversed triangle. 
The sucker of all the remaining Athericera consists of but 
two sete, the superior representing the labrum, and the infe- 
rior the ligula. 
They form three other small tribes which will correspond 
to the genera Cstrus and Conops of Linnzus, and to the 
Musca, Fab. as originally composed. 
As Stomoxys and Bucentes are connected with this last 
genus, we will begin with the tribe of the G{sTripEs con- 
sisting of the genus 
(Kistrus, Lin. 
Which is very distinct, as in place of the mouth we find but three 
tubercles, or slight rudiments of the proboscis and palpi. 
These Insects resemble large and densely pilose flies, and their 
hairs are frequently coloured in bands like those of the Bombi. 
Their antenne are very short; each one is inserted ina fossula over 
the front, ,and terminated by a rounded palette with a simple seta 
on the back near its origin. Their wings are usually remote; the 
alulz are large and conceal the halteres. The tarsi are terminated 
by two hooks and two pellets. 
These Insects are rarely found in their perfect state, the time of 
their appearance and the localities they inhabit being very limited. 
As they deposit their eggs on the ,body of various herbivorous 
quadrupeds, it is in woods and pastures that we must look for 
them. Each species of Céstrus is usually a parasite of one same 
species of some mammiferous animal, and selects for the location 
of its eggs the only part of its body that is suitable for its larve, 
whether they are to remain there, or pass from thence to the spot 
suited for their development. The Ox, Horse, Ass, Rein-deer, 
Stag, Antelope, Camel, Sheep and Hare are the only quadrupeds 
yet known, which are subject to be inhabited by the larve of the 
Cistri. They seem to have an extraordinary dread of the Insect 
when it is buzzing about them for the purpose of depositing its 
eggs. 
The domicil of the larve is of three kinds; we may distinguish 
them by the names of cutaneous, cervical, and gastric, as some live 
