624 
DIPTERA. 
9 
Bracy Clark, Esq., who has published some very inter¬ 
esting remarks ’^ on the hots of horses and of other animals, 
maintains that bots are rather beneficial than injurious to 
the animals they infest. His principal 'work on this sub¬ 
ject I have not yet seen. The maggots (Fig. 
273) of the CEstrus hovis^ or ox bot-fly, live 
in large open boils, sometimes called Avornils 
or wurmals, that is, worm-holes, on the backs 
of cattle. The fly is rather smaller than the 
horse bot-fly, although it comes from a much larger mag¬ 
got. The sheep bot-fly ( Cephalemyia ovis) lays its eggs 
in the nostrils of sheep, and the maggots crawl from thence 
into the hollows in the bones of the forehead. Deer are 
i 
also afflicted by bots peculiar to them. Our native hare, 
or rabbit, as it is commonly called, sometimes has very 
large bots, which live under the skin of his back. The 
fly QCEstrus huccatus) is as big as our largest humble-bee, 
but is not hairy. It is of a reddish-black color ; the face 
and the sides of the hind body are covered with a bluish 
white bloom; there are many small black dots on the lat¬ 
ter, and six or eight on the face. This fly measures seven 
eiffliths of an inch or more in leno:th, and its wind’s ex- 
pand about three quarters of an inch. It is rarely seen ; 
and my only specimen was taken in the month of July, 
many years ago. 
At the very end of this order is to be placed a remarkable 
group of insects, which seems to connect the flies with the 
true ticks and spiders. Some of these insects have wings; 
but others have neither wings nor poisers. Of the winged 
kinds there is one (^Hippohosca equina) that nestles in the 
hair of the horse; others are bird-flies ( Ornithomyia)^ and 
live in the plumage of almost all kinds of birds. The wing- 
* “ Observations on the Genus CEstrus,” in the Transactions of the Linngean 
Society, Vol. III. p. 289, with figures; “ On the Insect called Oistros by the An¬ 
cients,” in Vol. XV. of the same work; and “An Essay on the Bots of Horses and 
other Animals,” 1 vol. 4to (Lond., 1815). 
