BOTS. 2,65 



of the stomdch or bowels. Too many horses have been killed 

 by its destructive ageucy to render its use advisable. 



BOTS. 



These are the larvae of the gad-fly. During the summer 

 months, when the horse is at grass, the parent fly is seen busily 

 engaged in depositing its eggs upon the 

 hairs of the animal in such places as are 

 easily reached by his mouth. This seems 

 to be an instinctive feature in this insect. 

 The legs, shoulders, and body are the parts 

 selected for this purpose. The gad-fly is 

 seen hovering in an upright position when ^^^^^^^ gad-flt oe bot. 

 about to deposit her egg ; she then darts upon the horse, fixing 

 the egg to the hairs by means of a glutinous substance ; she 

 again prepares another, which is deposited in like manner, until 

 many hundreds are observed covering the hairs of the animal. 

 The rapidity with which these eggs are prepared and deposited 

 is astonishing. They are taken into the mouth by the animal 

 biting or licking himself or his mate, and are hatched upon the 

 tongue, or taken into the stomach and there hatche'd. If the 

 eggs are recently produced, they pass into the stomach before 

 they are hatched ; but if they remain for a considerable time 

 upon the hairs, they are hatched by the warmth of the tongue, 

 and they pass into the stomach, where they are developed. 

 This fact may be easily and satisfactorily proven by taking the 

 newly deposited egg in the hand, and then applyiug a warm 

 fluid ; when it will be observed that the egg is softened or dis- 

 solved, but does not produce the bot ; whereas, if the egg be 



