HOUSE FLIES OTHER THAN MUSCA 347 



may cause confusion. One of these is the so-called ' Lesser house fly ', 

 Homohmyia canicnlaris, L., which belongs to the family Anthomyidae 

 (see page 312). This fly is smaller and of a slenderer build than Mttsca 

 domestica. Its thorax is of a dark grey colour, and has no distinct lon- 

 gitudinal stripes. If its wing is examined with a pocket lens, it will be 

 noted that the fourth longitudinal vein, instead of bending up in its 

 terminal portion as in the case of Musca, runs out to the margin of the 

 wing parallel with the vein above it. In the resting position its wings 

 lie closer together than in Musca. 



Homohmyia scalaris has also been recorded from houses ; it is larger 

 but in many respects similar to canicnlaris. Occasionally Anthomyla 

 radicum may be seen on window panes in houses, especially if there 

 is any manure in the vicinity. It also has the characteristic anthomyid 

 venation and attitudes. 



The ' Stable fly', Stomoxys calcitrant may at times be found on win- 

 dow panes ; it is a little larger than Musca domestica, but cannot be mis- 

 taken for it. Its long dark proboscis, which projects horizontally from 

 the under surface of its head, will at once serve to distinguish it. 



Muscina stabulans is another fly which is occasionally to be seen on 

 window panes in European countries ; it is not at all unlike Musca 

 domestica in general appearance. It has four somewhat indistinct 

 longitudinal stripes on the dorsum of its thorax ; the wing venation 

 differs from Musca, for the fourth longitudinal vein does not turn up 

 sharply, but bends up gradually, leaving the first posterior cell widely 

 open, as in Stoinoxys calcitrans. 



In the tropics the worker will have many species of Musca to deal 

 with, and he will find considerable difficulty in recognizing them. He 

 may find Philaematoinyia insignis on window panes, especially if there are 

 cattle in the vicinity ; it is not a house-frequenting species like Stoinoxys 

 calcitrans, and only comes into rooms by accident. The several species 

 of the non-biting, blood-sucking muscids, which will be described further 

 on, are also extremely like Musca domestica ; they are, however, not 

 house flies and only very occasionally come into rooms. 



Sometimes a specimen of Morellia or Myospila may be seen in a house. 

 The former is a greyish, somewhat metallic insect, with two broad 

 stripes on the thorax ; the fourth longitudinal vein has a broad curvature 

 near its middle, and the first posterior cell opens narrowly. Myospila 

 are non-metallic species very like Musca domestica, but the wing vena- 

 tion is similar to that of Morellia. 



It is interesting to note that in America, out of 23,087 flies caught in 



