Bots ; their Nature. 281 



their eggs in the hair of the horse, to which they 

 adhere by a glutinous substance with which they 

 are surrounded, and in a few days the eggs are 

 hatched, and the minute grubs are set at liberty. 

 This is done by the horse licking itself, and the 

 little grubs adhering to the tongue of the horse 

 are carried into its stomach with its food. These 

 small caterpillars are provided with a small hook 

 on each side of the mouth, by means of which 

 they cling pertinaciously to the cuticular portion 

 of the stomach, and so tenaciously do they adhere, 

 that the hook will break before they leave their 

 hold. These pests contrive to locate during the 

 winter and to the end of the following spring on 

 the mucous of the stomach, by which time they 

 attain a fully-grown size, and must then, accord- 

 ing to the law of Nature, undergo a new trans- 

 formation. They quit their hold of the coating 

 of the stomach, and are carried along with the 

 food, from thence they pass into the intestinal 

 canal along with chyme, and are at length dis- 

 charged with it. These caterpillars thus evacu- 

 ated seek an appropriate place in the ground, 

 where they assume a chrysalis condition ; remain- 

 ing in this state for some weeks, they at length 

 break out from their swathing and assume the 

 form of a perfect insect ; immediately after this, 

 the male and female pair. The latter becoming 

 impregnated, sets about seeking an appropriate 

 place to deposit its eggs, which in imitation of 

 the parent, they ^n on the hair of the horses' legs, 

 to become in their turn a pest to the horse. The 

 treatment I have given elsewhere for worms 

 should be adopted for these pests. 



