15 



food consists of green algal growths." There are, however, good 

 grounds for thinking that the chief breeding-place of the species 

 of Phlebotomus is not the soil, but the dark and damp inner surface 

 of the lower parts of the walls and woodwork of permanent latrines, 

 privies, and cesspools, above the level of the fluid contents. That 

 these flies are common in latrines is a well-known fact, which has 

 been observed in localities so widely different as Herzegovina, 

 Egypt, Ashanti, and Uganda ; and Doerr, while admitting that the 

 true breeding-place of Phlebotomus papatasii is not yet known, 

 mentions facts tending to show, by a process of exclusion, that in 

 at least one military camp in Herzegovina the latrines can be the 

 only possible breeding-ground in the height of summer, that is at 

 a time when " Pappatacis " are most abundant and the soil 

 everywhere absolutely parched up by the heat of the sun. 



It would seem that after being fertilised the female Phlebotomus 

 needs a meal of blood for the development of her eggs, even though 

 the insect may have sucked blood before copulation. According 

 to Grassi, the eggs of Ph. papatasii are rather more than 0.5 mm. 

 in length, elongate oval in shape, and, when seen under a microscope, 

 light brown in colour, with longitudinal dark streaks connected 

 here and there by cross-lines : each female deposits about forty 

 eggs, which are usually scattered over an area of a few centimetres, 

 and, though some may lie in contact with each other, are not 

 deposited in a heap. The eggs of the Indian species observed by 

 Hewlett would appear to be considerably smaller than those of 

 Ph. papatasii. Howlett writes : " The eggs are .10 mm. to .15 mm. 

 in length, oval-cylindrical, very slightly curved, and rounded at 

 both ends. They vary in colour from yellowish to dark brown, 

 being white when new-laid, and subsequently show in some species 

 a pattern of hexagonal reticulations, in others more or less parallel 

 zig-zag lines of darker colour. In number they vary from 30 to 80, 

 the larger numbers being laid as a rule by the smaller species. 

 Oviposition under natural conditions has not been observed, but 

 in captivity the female moves about dropping here and there single 

 eggs ; the eggs when extruded are covered with a slightly sticky 

 film and adhere to the surface on which they fall. When an area 



