404 



DIPTERA. 



Fig. 323. 



ground, and there becomes a coarctate pupa, enclosed within 

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

 means of four trachese. 



The genus Gastrophihis has very small- 

 mouth-parts, the deep lying palpi being 

 somewhat spherical, and the 

 prol)OScis nearl}^ 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 larvie are introduced into the stomach. 

 The body of the larva widens posteriorly ; tlie 

 mandibles are not visible, and the maxilliij con- 

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

 larva grapples and adheres to the walls of the 

 horse's stomach. The rudimentary antennte are 

 indicated b}' an ocellus-like point. The Horse Bot-fly, Gas- 

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

 state is pale yellowish, spotted with red, with a grayish yellow 

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



Fig. 325. a 



though rarel}', 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 larva? live from May till October, and when fully grown, 

 Uang b}^ their mouth-hooks on the edge of the rectum, whence 



