36 FLIES FOUND IN HOUSES 



ten or fifteen minutes many flies were hovering about the food 

 and some eggs had ah'eady been deposited. That the compound 

 eyes so prominent in the SarcophagidcE are of importance in 

 orientation we are reasonably certain. If these insects were 

 deprived of their eyesight, food would probably be found with 

 difficulty. In several cases the eyes of Sarcophaga saTvacoiice 

 were painted with India ink, affecting the flies in a manner 

 similar to that of animals whose semicircular canals are disturbed. 

 Orientation was almost completely lost for a time. On placing 

 the individuals on their backs they were barely able to right 

 themselves after frantically using both legs and wings. They 

 crawled about on the table in an aimless manner, or on the 

 writer's fingers. After a few minutes they flew slowly away, 

 buzzing noisily, passing over several pieces of fish placed on the 

 table. Their flight was directed towards a window which they 

 struck with a thud. From this it would seem that light was not 

 perfectly excluded. No doubt much of the disturbance was due 

 to the penetration of the India ink" (Hermes, I, 1907, p. 49). 



Many species of the SarcophagidcE are viviparous, producing 

 numerous small maggots at birth. The larvae live in filth and 

 carrion of all kinds, and have also been found in wounds and 

 in the nasal passages and intestines of man. They resemble the 

 larvae of Chrysomyia (Chap. XXIl), the segments being separated 

 by well-marked constrictions, but the spines on the segments 

 are very minute. 



The flies are greatly attracted to putrefying animal remains 

 and excreta, and frequently settle on food, which they may infect 

 occasionally with disease producing bacteria. 



Sepsis punctiim Meig. Dung fly. 



A small glistening black or violet, slender fly, resembling the 

 cheese fly. (PI. VII, fig. i.) 



Length. 4 — 5 mm. ; span of wings 8 mm. 



Head. Round, deep violet in colour, and as broad as the thorax. The eyes are 



separated by an area equal to half the diameter of the head. There are strong 



bristles on the vertex. Cheeks and face dark yellow. Antennae dark yellow, 



with the terminal joint swollen and the arista bare. 

 Thorax. Brighter coloured than head, with three longitudinal lines produced by rows 



of minute hairs ; strong laterally directed bristles on thorax and scutellum. 



