38 FLIES FOUND IN HOUSES 



in ? . Frontal margins of orbits, cheeks and face yellow. Facial bristles very 



marked. Antennae dark brown, arista bare except the upper third which is 



slightly feathered. 

 lltorax. In c? yellowish brown, marked with longitudinal stripes. Below the wings 



are numerous bright yellow hairs, and on the dorsal side and scutellum many long 



black bristles. In ? colour darker, stripes more plainly marked, and hair below 



wings absent. 

 Wings. Clear, but slightly yellow ; anterior cross vein very distinct, with slight 



smoky colouration round it. Squama small. Halteres long and distinct and not 



covered by squama. 

 Legs. Femur brownish yellow, and covered with long yellow hair ; other parts 



yellow and not hairy in i . In ? femur dark and clothed with a few dark 



hairs. 

 Abdoinat. In S bright yellow and very hairy. The most prominent hairs are 



arranged in fringes on the posterior margins of the segments. In ? yellowish 



brown, and not hairy. 



This fly may often be seen in large numbers on animal 

 excreta, especially cow dung. It also frequents flowers, and is 

 predaceous, attacking various species of flies. It is rarely found 

 in town houses, but very frequently finds its way into country 

 houses and farm buildings. 



The larvae live in animal excreta, and the pups are also 

 found in this material. Probably this insect, which is not 

 attracted to food, plays little or no part in the spread of disease 

 producing bacteria. 



DrosopJiila fenestraruin. Fruit fly. 

 A very small pale yellow fly. (PI. IX, fig. i.) 



Loigth. 2 mm. ; span of wings 6 mm. 



Head. Round and as broad as thorax. Eyes reddish. Frons, cheeks and face pale 

 yellow. Bristles on vertex and frontal margin of orbit very marked. Antenna 

 yellow, terminal joint swollen, and arista with upper and lower bristles. 



Thorax. Darker yellow, with lines of very minute hairs ; some bristles laterally and 

 on scutellum. 



IVmgs. Clear, with peculiar venation. Halteres large and broadly expanded. 



Legs. Pale yellow. 



Abdomen. Pale yellow, with some bristles of medium length. 



" The species of this family are always small, seldom exceed- 

 ing a length of 5 to 6 mm., and usually from one to three ; of 

 rather plump appearance, giving a feeling of coldness to the 

 fingers when grasped. The bristles of the front are usually 

 conspicuous, but the body is without hairs" (Williston, 1908, 

 p. 299). 



