286 DISEASES OF THE STOMACH. 



and leaves the 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 : this is repeated by these flies until 

 four or five hundred eggs be sometimes placed on one horse.^^ 

 The parts chosen for the deposition of the eggs are those 

 liable to be licked by the tongue : the inside of the knee is a 

 favorite spot, and, next to this, the side and back part of 

 the shoulder, and, less frequently, the extreme ends of the 

 hairs of the mane. Now, the common notion is, that the 

 ova are licked off the skin, and so carried into the 

 stomach; but Mr. Clarke observes, ^'^I do not find this to be 

 the case, or at least only by accident; for, when they have 

 remained on the hair four or five days, they become ripe, 

 at which time the slightest application of warmth and 

 moisture is sufficient to bring forth in an instant the latent 

 larva. At this time, if the tongue of the horse touches the 

 egg, its operculum is thrown open, and a small active worm 

 is produced, which readily adheres to the moist surface of 

 the tongue, and is from thence conveyed with the food to 

 the stomach.'' And it appears, that the irritation of the 

 common flies proves the instigation of the animal's licking 

 himself; not, however, that this is absolutely necessary, for 

 " a horse that has no ova deposited on him, may yet have 

 bots, by performing the friendly office of licking another 

 horse that has." The larva or worm, being hatched and. 

 lodged in the stomach, immediately clings, by means of its 

 tentacula — two dark brown hooks, between which is its 

 mouth — to the cuticular coat, which they pierce, though 

 they never insinuate their points into the muscular or 

 sensitive tunic beyond it : in this manner, so pertinaciously 

 does the bot adhere that, in our attempts to unhitch it, it 

 will frequently suff'er its hooks to be broken, or even its body 

 severed, rather than quit its hold. Now and then, but I 



