580 THE COMPLETE GRAZIER. BOOK vi. 



attached by the female hot fly to the hairs of the horse. The hair of 

 the mane, the shoulders, and the inside of the knee, are places especially 

 chosen for egg-laying. The method of deposit is for the female fly to 

 poise near the horse, and then, flying at the spot, to leave the egg 

 fixed to the hair by a glutinous moisture, and so to continue until four 

 or five hundred eggs may be laid on one animal. Her whole supply is 

 believed to be as many as seven hundred. 



The eggs are ready to hatch in a period variously stated as from 

 about five days to three weeks. How the maggots are conveyed into 

 the horse does not appear to be an absolutely settled thing ; some may 

 possibly creep through the hair to the mouth. The most commonly 

 received opinion, however, is, that the moisture and warmth from the 

 horse's tongue when he licks the spots where the eggs are attached 

 hatches them, or, rather, helps to free the maggot if near hatching 

 time, and the maggot being produced adheres to the horse's tongue. 

 Thus a number of larvae from the many eggs laid are conveyed into the 

 mouth, whence they pass downwards, or are carried downwards with 

 food and water from the mouth to the stomach. 



There the maggots fix themselves to the mucous membrane by 

 means of two dark brown hooks (see Fig. 147, 4), one of which is placed 

 on each side of the slit which serves for a mouth, and there they 

 nourish themselves by suction. As they grow older they alter in shape, 

 and are considered to pass from eight to ten months in maggot state, 

 attached by their mouth hooks to the lining membrane of the non- 

 digestive portion (page 404) of the stomach. 



Fig. 150 shows a number of partly grown bot maggots attached to 

 the membrane of the stomach. By this time they have gained their 

 characteristic form, which is somewhat barrel-shaped, banded round at 

 intervals by lines of prickles or horny points. When full-grown they 

 loosen the hold of their mouth hooks, by which they have kept them- 

 selves in position, and passing along the intestines are discharged from 

 the animal, and fall to the ground. They bury themselves in the 

 horse dung, or in the ground, and there turn to brown chrysalids 

 (formed outside the hardened skin of the maggot), from which the fly 

 comes out in about six or seven weeks during summer. 



Prevention and Remedies. Combing, brushing, clipping hair at the 

 infested spots, and the use of soaps and washes, which would not be 

 in any way injurious to the horse, whilst they would help to clean off 

 eggs and maggots, are amongst the regular methods of treatment. Any 

 safe wash or smear with a strong odour of carbolic acid or mineral 

 oil, or any other scent obnoxious to the flies, would of course be a 

 deterrent of attack. 



An experienced veterinary surgeon states that he knows of no 

 medicine that will destroy the bots, or make. them leave their winter 

 quarters until fully developed. A good feed of grass in early spring 

 induces them to detach themselves the soonest. As a medicine, 2 oz. 

 of turpentine and 20 oz. of raw linseed oil mixed, and given as a 

 draught once a fortnight, is the best remedy ; i.e., if it is thought the 

 loss of flesh and condition by the horse is due to the presence of bots. 



