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notwithstanding the waste, the interior of the horse’s stomach may become 
completely covered with the larvae commonly termed “ bots.” 
When the bots, which hold on to the lining of the stomach by means of 
two large hooks, are perfectly grown, they release themselves, and are carried 
through the intestines along with the excreta, and thus they finally fall to the 
ground. They then bury themselves below the surface, in order to undergo 
a transformation from the condition of the bot, to that of the pupa or 
chrysalis. When they have remained thus buried for six weeks, they make 
their way out of their enclosing cocoons, and emerge as perfect gad-flies. 
The male insects die, but the females live long enough to deposit their eggs, 
which are generally about forty in number. The bot passes about eight 
months of its existence in the stomach, where it is present in the winter 
months. It leaves in spring or early summer. The fly is developed from 
June to September, and after the latest females have appeared, all perish in 
October. Not uncommonly, the presence of bots in the stomach of the 
horse gives rise to considerable mischief. When very numerous, they may 
_ set up serious disease, sometimes even perforating the walls of the intestines, 
It is not always possible to diagnose the presence of bots in the stomach, 
but not unfrequently they may be seen in the excrement, or adhering 
around the anus. When there is reason to suspect their presence in very 
large numbers, it is well to place a piece of rock salt in the horse’s manger, 
and to administer a drench, consisting of spirit of ether two ounces, of 
glycerine of carbolic acid three drachms, and of linseed-oil a pint. This 
may be repeated once every day for four days. 
The accompanying pictures show the various forms assumed by the 
cestrus equi. A is the larva or bot, B is the pupa case, C is the male fly, and 
D is the female fly. There is another species of gad-fly called the cestrus: 
haemorrhoidalis, which deposits its eggs on the lips and nostrils of the horse. 
We need not speak at length here of the bot-fly of the ox, but may mention 
that, unlike the bot-fly of the horse, it passes its larval stage as a bot beneath 
the skin of its host, and it is this larva whose growth causes the appearance of 
