B0T8. 397 



tqui) which lays light, orange-coloured eggs, about the twentieth 

 of an inch in diameter, chiefly on the breast, front of the fore-arms, 

 and those parts of the shoulders and sides that are in reach of the 

 horse's tongue. The eggs are firmly attached to the ends of the 

 hairs of the coat, by a sticky fluid secreted by the fly. The bots, 

 which are about four-fifths of an inch in length, select for pre- 

 ference, as a residence, the left compartment of the stomach, in 

 which they may be found in scores, and sometimes even in hun- 

 dreds. 



2. The (/astrophilus hcemorrhoidalis lays its eggs on the muzzle 

 of the horse, which it appears to frigiiten by its approach. The 

 eggs are about the saaiie size as those of the first variety, but are 

 darker in colour, and the bots are smaller in size ; being about five- 

 eighths of an inch in length. Although the left compartment of the 

 stomach is their usual place of first temporary residence, they may 

 attach themselves to the mucous membrane of the passage between 

 the mouth and the respective openings of the gullet and windpipe. 

 They may also be met with in the right compartment of the stomach 

 and in the small intestine close to the stomach. Having remained 

 some months in their selected sites, they become detached, and 

 on reaching the lower portion of the rectum, fix themselves for 

 some time to the mucous membrane of that part. When in this 

 position, they often become exposed to view, on the horse strain- 

 ing when dunging. They are then of a green colour. 



3. Gastrophilus nasalis lays her eggs, which are white in colour, 

 on the lips and nostrils of the horse. These bots are of a light yel- 

 low colour and locate themselves in the small intestine close to the 

 stomach. When they are of full size, they are about three-fifths 

 of an inch in length. Their presence in the intestine is apt to give 

 rise to colic. 



4. Gastroyliilus pecorum is frequently to be found in Eastern 

 Europe. Its eggs and bots closely resemble those of the g. hcemor- 

 rhoidalis in appearance and behaviour, except that its bots are red. 

 They also attach themselves to the lower portion of the rectum 

 before being finally exjDelled. 



EFFECT OF BOTS ON THE HEALTH OF THE HORSE.— Al- 

 though the fact of bots being inside a horse can be of no possible 

 advantage to him ; their presence, when in small numbers, is, as a 

 rule, productive of little or no ill consequences to their host. If 

 their number be large, they cannot help being a source of debility 

 and irritation. In more or less exceptional cases, they cause, espe- 

 cially among young horses, indigestion, loss of condition, and even 

 death. There have been cases of fatal interference with breathing 

 due to bots of g. liceuiorrhoidalis lodging about the larynx. These 



