FLIES FOUND IN HOUSES 



31 



Proportion of sexes. "Great disparity in the proportion of 

 males to females is found in this species as it occurs in houses. 

 Hamer showed in 1909 that the males constitute from 75 to 85 

 per cent, of the total flies of this species caught in balloon traps 

 and on fly papers. This, however, does not indicate a disparity 

 in the proportion of males to females in the species, as I have 

 found that the females are more common out-of-doors, especially 

 in the neighbourhood of the breeding places" (Hewitt, IX, 1912, 

 p. 163). 



Fig. 14. 

 (From Hewitt, Report to Local Government Board, 



Fig. 13- 

 Fig. 13. 'Lz.rva.oi F.canicula)-is 



191-2, reduced by one-iialf.) 

 Fig. 14. Part of right middle femur and tibia of F. canicidaris. (From Hewitt, 



1912.) 



The eggs are white and cylindrically oval. 



" The larva is wholly different from that of M. do/nestica ; its body being provided 

 with a number of appendages or spiniferous processes. These are arranged in three 

 pairs of longitudinal series and there are in addition two pairs of series of smaller 

 processes. 



" The body is compressed dorso-ventrally and the surface is roughened in character 

 and in places spiniferous. It consists of twelve segments, of which the first, or pseudo- 

 cephalic segment, is often withdrawn into the second or prothoracic segment. The 

 posterior end of the body is very obliquely truncate. The full-grown larva measures 

 5 to 6 mm. in length. The three series of pairs of spiniferous flagelliform processes, 

 or appendages, are arranged as follows : A dorsal series consisting of ten pairs of 

 processes commencing with an antenna-like pair of processes at the anterior border of 



