352 MEDICAL ENTOMOLOGY 



may be seen either on cattle sucking up blood or serum which exudes 

 from the bites of other flies, or on patches of fresh cow dung laying its 

 eggs. It was originally described from China, and according to Bezzi it 

 occurs in parts of Africa. 



The worker in India who encounters for the first time any one of these 

 three species of Mitsca may find some difficulty in distinguishing them ; the 

 following distinguishing points may be useful : Both sexes of pattoni 

 are distinctly larger than those of gibsoni. In the male pattoni the 

 thoracic bands are broader, the thorax is lighter in colour, the longitu- 

 dinal median band is narrower on the first and second abdominal seg- 

 ments, but broader on the third segment, than in gibsoni ; the silvery 

 patches are broader, but the brown lateral bands are lighter than those 

 of gibsoni. In the case of the female pattoni, the longitudinal band on 

 the first segment is much narrower than that on the first segment of 

 the female gibsoni. The lateral brown bands on the abdomen of pattoni 

 are broader and lighter in colour, and the transverse black bands at the 

 lower borders of the first three segments less conspicuous than those 

 of gibsoni. 



Convexifrons, which bears a superficial resemblance to gibsoni, is 

 a distinctly smaller fly ; the male has a yellowish abdomen, while that of 

 the female in some lights is almost uniformly reddish brown. The 

 longitudinal band on the second segment of the female convexifrons 

 is much broader than the corresponding band of gibsoni, and the dark 

 lateral bands are not nearly so conspicuous as those on the latter fly. 



Musca nigrithorax, Stein. Male- Front very narrow ; thorax black 

 with small grey patches on the shoulders. Abdomen bright ochraceous, 

 and without any markings. 



Female. Front wide ; thorax dark with a faint indication of two 

 black longitudinal stripes, and a dark central one. Abdomen as in male. 



This handsome little fly will be recognized by its dark thorax and 

 unbanded abdomen. In Madras it is only seen on cattle, and behaves in 

 the same way as the other blood-sucking species described above. It 

 also occurs in Java. It breeds in cow dung. 



Musca bezzii, Patton and Cragg. Male. Thorax, dark grey to bronze 

 grey, with four black longitudinal bands. Abdomen ochraceous buff 

 with shimmering yellowish patches ; first segment with a black transverse 

 band, not extending to the outer and lower borders. Second segment 

 with a broad median longitudinal band, and a silvery patch on each side. 

 Third segment with a narrower longitudinal band, a rectangular yellow- 

 ish grey to silvery grey patch on either side, and a brown rectangular 



