THE HORSE EOT FLY. 133 



CHAPTER XC. 



THE HORSE EOT FLY. 

 {Gastrophilus equi, Fabr.} 



The present chapter on this pest of the wild, also of 

 the domesticated, horse is mainly taken from the late 

 Miss Ormerod's articles kindly sent to me by the writer, 

 also from the personal observations of others, including 

 myself ; the illustrations on our plate having been drawn 

 by Mr. Brittlebank from nature from specimens in the 

 museum at my office. In the case of the " Horse Bot 

 Fly, n sometimes also called the " Horse Bee," the 

 method of infestation may be shortly described as 

 follows : The female fly (Fig. VII.) lays her eggs for 

 the most part on the hairs of the mane, shoulders, and 

 chin, or on the forelegs, where they can be reached by 

 the tongue of the horse. By this means the eggs, or 

 the maggots hatching from them, can be readily licked 

 into the mouth, and then the maggots pass down into 

 the stomach (Fig. X.). There they fix themselves by 

 their mouth hooks (Figs. IV. and V.), and feed by 

 suction till after three-quarters of a year (but a much 

 shorter time in Victoria C.F.) ; when they are full 

 grown they lose hold, and pass out of the horse in the 

 usual manner. In the dung or in the ground they bury 

 themselves, and turn to a hard, dark colored crysalis, 

 in which the fly forms, and from which it comes out, in 

 summer, after about six or eight weeks (in Victoria 

 probably about half that period C.F.). This is the 

 life history shortly given, but the following details 

 describe the chief points of infestation, of which the 

 knowledge is commonly needed for practical use. The 

 flies (Figs. VI. and VII.) are half an inch, or somewhat 



