502 THE HORSE. 
papille are shown on the engraving, which delineates also the appearance 
of the bots themselves, so that no one can fail to recognise them when he 
GaRoUP OF BOTS ATTACHED TO THR STOMACH. 
sees them. This is important, for it often happens that a meddlesome 
groom when he sees them expelled from or hanging to the verge of the 
anus, as they often do for a short time, thinks it necessary to use strong 
medicine ; whereas in the first place he does no good, for none is known 
which will kill the larva without danger to the horse, and in the second, 
if he will only have a little patience, every bot will come away in the 
natural course of things, and until the horse is turned out to grass, 
during the season when the cestrus deposits its eggs, he will never have 
another in his stomach. 
THE @STRUS EQUI comes out from the pupa state in the middle and Jat- 
ter part of summer, varying according to the season, and the female soon 
finds the proper nidus for her eggs in the hair of the nearest horse turned 
out to grass. She manages to glue them to the sides of the hair sc 
firmly that no ordinary friction will get rid of them, and her instinct 
teaches her to select those parts within reach of the horse’s tongue, such 
as the hair of the fore legs and sides. Here they remain until the heat of 
the sun hatches them, when, being no larger in diameter than a small 
pin, each larva is licked off and carried down the gullet to the stomach, 
to the thick epithelium of which it soon attaches itself by its hooks. Here 
it remains until the next spring, having attained the size which is repre- 
sented in the engraving during the course of the first two months of its 
life, and then it fulfils its allotted career, by letting go and being carried 
out with the dung. On reaching the outer air it soon assumes the 
chrysalis condition, and in three or four weeks bursts its covering to 
become the perfect insect. 
From THIS HISTORY it will be evident that no preventive measures will 
keep off the attacks of the fly when the horse is at grass, and, indeed, in 
those districts where they abound, they will deposit their ova in the hair 
of the stabled horse if he is allowed to stand still for a few minutes. 
The eggs are, however, easily recognised in any horse but a chestnut, to 
which colour they closely assimilate, and as they are never deposited in 
large numbers on the stabled horse they may readily be removed by the 
groom. Unlike other parasites, they seem to do little or no harm. on 
account of the insensible nature of the part of the stomach tc which they 
