356 THE HORSE. 



tremity of the stomach is occupied with them, the interstices being 

 occupied by little projections which are caused by those that have 

 let go their hold, and have been expelled with the food. Several 

 of these papillae are shown on the engraving, which delineates also 

 the appearance of the bots themselves, so that no one can fail to 

 recognise them when he sees them. This is important, for it often 



FlG. 18. GROUP OF BOTS ATTACHED TO THE STOMACH. 



happens that a meddlesome groom when he sees them expelled 

 from or hanging to the verge of the anus, as they often do for a 

 short time, thinks it necessary to use strong medicine j whereas in 

 the first place he does no good, for none is known which will kill 

 the larva without danger to the horse, and in the second, if he will 

 only have a little patience, every bot will come away in the natural 

 course of things, and until the horse is turned out to grassj during 

 the season when the osstrus deposits its eggs, he will never have 

 another in his stomach. 



THE CESTRUS EQUI comes out from the pupa state in the middle 

 and latter part of summer, varying according to the season, and 

 the female soon finds the proper nidus for her eggs in the hair of 

 the nearest horse turned out to grass. She manages to glue them 

 to the sides of the hair so firmly that no ordinary friction will get 

 rid of them, and her instinct teaches her to select those parts 

 within reach of the horse's tongue, such as the hair of the fore 

 legs and sides. Here they remain until the heat of the sun hatches 

 them, when, being no larger in diameter than a small pin, each 

 larva is licked off and carried down the gullet to the stomach, to 

 the thick epithelium of which it soon attaches itself by its hooks. 

 Here it remains until the next spring, having attained the size 



