1 68 DURHAM BlPTERA. 



XXVIII. 



17 (18). Third antennal joint long. Upper outer angle of 



0.4 2 rectangular. Orthoneura, Mcq. (275) 



18 (17). Third antennal joint short. Upper outer angle of 



0.4 2 acute. 



19 (20). Abdomen all shining. Male eyes distant. 



Liogaster, Rnd. (276) 



20 (19). Abdomen dull on its disc. Male eyes touching. 



Chrysogaster, Mg. (277) 



21 (14) (22). Species with abdomen all orange. 



Brachyopa, Mg. (297) 



22 (14) (21). Species with pale abdominal markings, or if 



unicolorous or all dark, then without eye margins 

 on furrowed frons. 



23 (30). Abdomen narrow at the base, club-shaped. 



24 (25). Abdomen very long and narrow. Baccha, F. (292) 



25 (24). Abdomen only moderately long. 



26 (27). Hind femora simple. 



291. Doros, Mg. (145 1. conopseus, F.) 



27 (26). Hind femora much thickened. 



28 (29). Lower outer corner of 0.4 2 rounded. 



Sphegina, Mg. (295) 



29 (28). Lower outer corner of 0.4 2 almost a right angle. 



Ascia, Mg. (296) 



30 (23). Abdomen only slightly narrow at the base, ovate, or 



oblong. 



31 (32). Hind femora much thickened. 



306. Myiolepta, Newm. (Milesinae). 

 (159 1. luteola, Gmel.) 



32 (31). Hind femora normal. 



33 (34). Face without a central knob, and the mouth produced 



snout-like (VI. 16). Rhingia, Scop. (295) 



34 (33). Face with a central knob, and seldom with a much 



produced mouth edge. 



35 (44). Face all dark without any yellow. 



36 (37). Abdomen somewhat club-shaped with red blotches. 



Wings shorter than the abdomen. 



Pyrophvena, Schin. (280) 



