OESTRUS. 
367 
O. Eqid^ resides in the stomachs of horses, and 
the O. xjeterinus of Mr. Clark, the larva of which 
is also found in similar situations. The O. tne- 
morrhoidalis is about the size of a common win- 
dow-fly, with pale dusky wings, brown thorax, 
abdomen white at the base, black in the middle, 
and red at the tip. The O. Teterinus is nearly of 
similar size with the O. Equi, and' is entirely of a 
ferruginoits colour, with the abdomen more dusky 
towards the tip. 
The exotic Oestri are probably numerous, but 
are at present very little known. 
Whether the formidable African Fly, described 
by Mr. Bruce under the name of Zimb* or Tsalt- 
salya may be referred to this genus or not, I shall 
not pretend to determine: there are however some 
particulars in its history which would lead one to 
suppose it an Oestrus. 
This insect (says Mr. Bruce,) is a proof how 
fallacious it is to judge b}^ appearances. If we 
consider its small size, its weakness, want of variety 
or beauty, nothing in the creation is more con- 
temptible and insignificant. Yet passing from 
these to his history, and to the account of his 
powers, we must confess the very great injustice 
we do nim from want of consideration. We are 
obliged, with the greatest surprise, to acknow- 
ledge, that those huge animals the Elephant, the 
Rhinoceros, the Lion, and the Tiger, inhabiting 
the same woods, are still vastly his inferiors, and 
* Bruce’s travels, vol. I. p. 388, and vol. V. p. 188, 
