(113) 



354 C. GORDON HEWITT. 



domestica and M. corvina. It will be seen, therefore, 

 that its breeding habits are very similar to those of M. 

 domestica and the sub-species determinata. It is in- 

 teresting and important to note the rather exceptional choice 

 of cow-dung as a breeding-place. 



(8) Homalomyia canicularis L. 



This species of fly (see ' Quart. Journ. Micr. Sci./ vol. 51, 

 PI. 22, fig. 3) is often mistaken by the uninitiated for M. 

 domestica which are not full grown. Although it may be 

 called the small or lesser house-fly its differences from M. 

 domestica are great, as it belongs to a different group of 

 calypterate Muscidae, namely, the Anthomyidge. One of the 

 chief distinguishing features of this group is that the fourth 

 longitudinal vein of the wing (M. 1 + 2) goes straight to the 

 margin of the wing and does not bend upwards at an angle 

 as in M. domestica. 



The male of H. canicularis differs from the female in 

 some respects. In the male the eyes are close together, and 

 the frontal region is consequently very narrow ; the sides of 

 this, these are the inner orbital regions, are silvery white, 

 separated by a narrow black frontal stripe. In the female 

 the space between the inner margins of the eyes is about one 

 third of the width of the head; the frons is brownish black, 

 and the inner orbital regions are dark ashy grey. The bristle 

 of the antenna of H. canicularis is bare; in M. domes- 

 tica, it will be remembered, the bristle bears a row of setae 

 on its upper and lower sides. The dorsal side of the thorax 

 of the male is blackish grey with three rather indistinct longi- 

 tudinal black lines. In the female it is of a lighter grey, and 

 the three longitudinal stripes are consequently more distinct. 

 The abdomen of the male H. canicularis is narrow and 

 tapering compared with that of M. domestica. It is bronze 

 black in colour, and each of the three abdominal segments 

 has a lateral translucent area^ so that when it is seen against 

 the light, as on a window-pane, three, and sometimes four, 

 pairs of yellow translucent areas can be seen by the trans- 



