BOTS li\ HORSES. 131 



pose, curved inwards and upwards : in this way she approaches Ihe part 

 wliere she designs to deposit the egg : and suspending herseil' tor a few 

 seconds before it, suddenly darts upon it and leaves the egg adhering to 

 the hair ; she hardly appears to settle, but merely touches the iiair 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 

 various flies, till 4 or 500 eggs are sometimes placed on the horse. 



The inside of the knee is the part on which these flies are most 

 fond of depositing their eggs, and next to this on the side and back part 

 of the shoulder. It is a fact worthy of attention, that the fly does not 

 place them promiscuously about the body, bnt constantly on those parts 

 most liable to be licked with the tongue, and the ova therefore are al- 

 ways scrupulously placed within its reach. 



Some persons suppose that the eggs are loosened from the hairs by 

 the moisture of the horse's tongue, aided by its roughness, conveyed to 

 the stomach and there hatched. Many eggs may thus be conveyed, but 

 it is probable they pass on to the intestinal canal before they are hatch- 

 ed, and thus perish. The fact seems to be this — when they have re- 

 mained on the hairs four or five days, they become ripe, after which 

 time, the slightest application of warmth and moisture is sufficient to 

 bring forth in an instant the latent grub. 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 thence conveyed with the food to the stomach. 



It is fortunate for the animals infested with these insects, that their 

 numbers are limited by the hazards to which they are exposed. I 

 should presume that a hundred are lost for one that arrives at the per- 

 fect slate of the fly. The eggs, in the first place, when ripe, often hatch 

 of themselves, and the larva without a nidus, crawls about till it dies : 

 others are washed off" by the water, or are hatched by the sun and mois- 

 ture, thus applied together. 



When in the mouth of the horse, they have the dreadful ordeal of 

 the teeth and mastication to pass through. On their arrival in the stom- 

 ach, they may pass, mixed with the mass of food, into the intestines; 

 and when full grown, on dropping to the ground in the natural way, a 

 dirty road, or water may receive them. If in the fields, they are in 

 danger of being crushed to deatli, or being picked up by birds. Sucfi 



