226 ODONTOGNATHUS, @STRUS. 
0. 
4—1, Oponroenatnus. Spec. 1 
aculeata, compressed ; lower jaw longest. 
See MS P. 
8—1i2. Ckstrus. Spec. 12. 
bovis, (gad-fly,) wings brown without spots 3 ab- 
domen with a black band in the middle, and 
orange-yellow hairs at the tip. Deposites its 
eges “under the skin of cattle, which causes 
them to run and bellow when in the larva state. 
equ?, (leg nitter,) wings whitish with a black band 
in the middle and two dots at the tip. Depo- 
sites its eggs on the hairs of horses’ legs in the 
the summer months. 
hemorrhoidalis, (lip nitter,) wings brownish with- 
out spots ; abdomen black, the base white and 
fulvous at the tip. Deposites eggs on the lips 
of horses. 
veterinus, (throat nitter, bot-fy,) wings without 
spots ; body ferruginous ; sides of the thorax. 
and base of the abdomen with white hairs. A 
little smaller than the leg nitter. Deposites 
eggs under the skin of the throat of horses in 
September. 
Remarks. The three last species are the nit- 
_ters so well known in this country ; particularly 
the leg and throat nitters. It is the received opin- 
ion that the nits on the legs of horses, are taken 
into the mouth of the borse, conveyed into the 
intestines, and at length become the bot larva. 
This is a very extravagant conjecture and requires 
proof. 
