260 DURHAM DIPTERA. 



XXXIII. 454. 



13 (2). Three post-sutural bristles. 



14 (15). Mid tibiae inner side with strong erect bristles. 



(1950. Hyedotesia disfiar, Fin.) 



15 (14). Mid tibiae inner side without bristles. 



16 (19). Halteres black. 



17 (18). Abdomen dark grey, only slightly shining. 



(S. halterata, Stein) 



18 (17). Abdomen deep purple-black, very shining. 



(M. . steinti, Schnbl.) 



19 (16). Halteres pale, at most brownish yellow. 



20 (21). Dorsum grey, distinctly striped. (1977. M. allotalla.) 



21 (20). Dorsum uniform black or dark grey, unstriped. 



22 (23). Abdomen without a trace of paired spots ; large 



species 6-7 mm. i 1 ^!- >S- nigrinervis, Ztt.) 



23 (22). Abdomen, viewed from behind and from the side, 



with large triangular indistinct paired spots. 5 mm. 



(S. carbonella, Ztt.) 



24 (1). Legs all or partly yellow. 



25 (46). Legs with at least the base of the fore femora dark. 



26 (35). All femora wholly or for the most part dark. 



27 (32). Four post-sutural bristles. 



28 (29). Fore tibiae wholly or for the most part black, and 



without bristles. S. dufilicata, Mg. (1991) 



29 (28). Fore tibiae yellow, and with bristles on the middle. 

 30(31). Wings tinged with yellow ; abdominal spots usually 



wanting or small ; large species. 



(1994. S. quadrum, F.) 



31 (30). Wings almost clear; abdominal spots distinct; smaller 



species. (S. calceaia, Rnd.) 



32 (27). Three post-sutural bristles. 



33 (34). X-veins very distinctly clouded. (S. coihurnata, Rnd.) 



34 (33). X-veins only slightly clouded. 



(S. di/plaris, Stein [1993. atripes, Mde?]) 

 85 (26). The hind femora wholly, or almost wholly yellow. 

 36 (41). Abdomen with paired spots, which are very seldom 



wanting, in which case the abdomen is uniform 



grey. 



