404 



DIPTERA. 



ground, and there becomes a coarctate pupa, enclosed within- 

 the old larva skin, and remaining in connection with it by 

 means of four tracheae. 



The genus GastrojyJiilus has very small 

 mouth-parts, the deep lying palpi being 

 somewhat spherical, and the 

 proboscis nearly obsolete, 

 while the abdomen is sessile. 

 The species are of medium 

 size, short and thick, and very hairy. The female 

 deposits her eggs on the horse's hips and legs, 

 whence the larvse are introduced into the stomach. 

 The body of the larva widens posteriorly ; the 

 mandibles are not visible, and the maxillae con- 

 stitute the so-called mouth-hooks, by which the 

 larva grapples and adheres to the walls of the 

 horse's stomach. The rudimentary antennae are ^'^- ^^• 

 indicated by an ocellus-like point. The Horse Bot-fly, Gas- 

 tropliilus equi Fabr. (Fig. 323 ; fig. 324, larva), in its perfect 

 state is pale j^ellowish, spotted with red, with a grayish yellow 

 hirsuties ; the thorax is banded with black, or sometimes, 



though rarely, reddish hairs. The hinder trochanters are 

 hooked in the males, and tuberculated in the females, and the 

 wings are banded with reddish, with two spots at the apex. 

 The larvae live from May till October, and when fully grown, 

 liang by their mouth-hooks on the edge of the rectum, whence 



