LYPEROSIA: EARLY STAGES 375 



cell widely open. Palpi dark and slightly spatulate at their tips. This 

 species is found almost throughout India and Ceylon, and Africa : it was 

 originally described from Somaliland. 



Lyperosia exigua, Meij. (Plate XLIX, fig. 2.) A larges late grey to 

 dark grey species. Frons in male about one-fifth total width of head ; in 

 female one-third. Thorax, ash grey to dark grey, with two narrow well- 

 separated brown stripes. Abdomen dark grey, lighter at the upper end, 

 with a distinct narrow dark longitudinal median band on the first and 

 second segments. Palpi narrow and spatulate at tips. Third and fourth 

 veins converging towards their extremities, and first posterior cell 

 narrowly open. It is found throughout India, in Java, and other parts 

 of Central Asia. 



Lyperosia irritans, the type species of the genus, is popularly known 

 in the United States as the ' Horn fly ' from its habit of resting on the 

 horns of cattle ; minitta and exigua also have this 

 habit. Farmers and stockbreeders in the United States 

 believe that irritans deposits its eggs on the horn, and that when the 

 larvae hatch out they burrow into the skin and even penetrate the brain. 

 It is probable that this idea receives support from the fact that when a 

 large number of flies collect on the horn, the black excreta give it a 

 speckled or ' fly-specked ' appearance. 



When at rest the flies nearly always fold their wings in a scissor-like 

 manner over the abdomen ; when feeding they elevate their wings. 

 Exigua may often be seen on cattle, resting between the shoulders, or 

 higher up between the horns. All the species feed on the back and 

 flanks, seldom on the legs and abdomen. 



All the species of the genus Lyperosia lay their eggs in freshly dropped 

 cow dung. The females settle on the dung the moment it falls to 

 the ground, and lay the eggs either on the surface 



of the dung or in 'cracks; onlv one egg is laid in Brfldin * habits and 



early stages 



each place and at each act. Exigua, whose habits 



have been observed in Madras, usually lays about twelve eggs at a time. 

 The flies immediately return to the cow and the process is repeated when 

 dung is again dropped. The egg measures about 1*2 mm. in length, and 

 is of a light reddish colour, straight on one side and convex along the 

 other ; it has a deep furrow on the upper surface of the straight border 

 and the ends are spatuloid. The mature larva measures about 7*5 mm. 

 in length, and is of a dirty white colour ; the posterior stigmata are 

 close together ; otherwise it is very similar to the larvae of the other 

 Stomoxydinae. The larvae migrate from the dung when about to pupate, 



