OESTRUS. 
360 
tremely well described by Mr. Bracy Clark in 
the third volume of the Transactions of the Lin- 
nasan Society. It is a trifle smaller than the 
Oestrus bovls, and is of a yellowish brown colour, 
with a dusky band across the thorax, and the tip 
of the abdomen of similar colour: the wings are 
whitish, with a pale-dusky bar across the middle 
of each, and two dusky spots at the tip. 
The manner in which the young larvae or Bots 
are introduced into the stomach and bowels of 
the animal they infest is singularly curious, and 
cannot be better delivered than in the words of 
the ingenious observer. 
‘‘ When the female has been impregnated, and 
the eggs are sufficiently matured, she seeks among 
the horses a subject for her purpose, and ap]3roach- 
ing it on the wing, she holds her body nearly up- 
right in the air, and her tail, which is lengthened 
for the purpose, curved inwards and upwards: in 
this way she approaches the part where she de- 
signs to deposit her egg; and suspending herself 
for a few seconds before it, suddenly darts upon it, 
and leaves her egg adhering to the hair : she hardly 
appears to settle, but merely touches the hair with 
the egg held out on the projected point of the 
abdomen. The egg is made to adhere by means 
of a glutinous liquor secreted with it. She then 
leaves the horse at a small distance, and prepares 
a second egg, and, poising herself before the part, 
deposits it in the same way. The' liquor dries, 
and the egg becomes firmly glued to the hair: tliis 
is repeated by various flies till four or five hundred 
