1909.] 117 



62 (61). nind femora without such fringe. First thin vein of female only 



moderately curved at its origin. 



63 (64) Froiis high, scarcely broader than long. 



S 9 • Tliorax and abdomen black, postalar calli sometimes yellowish, pleural 

 bristles tender and simple ; antennae ratlier small, supra-antennal bristles large 

 and equal (J ) smaller and less equal (? ), palpi pale yellow, rather large and 

 prominent ; wings tinged with yellowish-brown and veins brownish, costa 

 barely to middle of wing, fringe fairly long, 1 usually shorter than 2 + 3 { $) 

 rather longer ( 9 ), angle at fork variable ; legs yellow, hind femora more 

 brownish, tibial cilia fairly large ; hypopygium small and grey, often partially 

 withdrawn within 6th segment and without bristles, the ventral phite small, 

 and the deep yellow anal organ stout and moderately long. 



H mm. altifrons, n. sp. 



64 (63) Frons low, about i broader than long. 



Four closely allied species full under this head. Common to all of them is a 

 moderately broad frons with full sized antennae, large and equal or nearly equal 

 supra-antennal bristles, and large and pi'ominent yellow palpi ; the costal fringe 

 is very long, the curve at the origin of the first thin vein gentle in the male 

 but more pronounced, though still moderate, in the female, and the tibial cilia 

 always distinct and generally large. 



65 (70) Firxt costal division not longer than the second, or if rather longer 



dintinctly shorter than the second and third together {variabilis). 



C^^ (67) Male hypopygium armed at the lower corners and on the sides with large 



and conspicuous bristles, almost identical in number and distribution 



loith those in humilis. 



<J 9 . Thorax and abdomen black, the latter with a greyish gleam, pleurae with 



1 or 2 bristles longer than the others ; wings tinged with yellowish-brown, 



costa more than half the wing length, angle at fork moderate but rather 



variable ; legs from yellowish-brown to almost black, fore tarsi slender ( $ ) 



somewhat stout ( 9 ) ; end of male abdomen (in good specimens) hairy as in 



humilis, hypopygium large, dull and grey and fully exposed as seems always 



to be the case when bristles are present, subanal body frequently extruded, 



very large and glossy black, the ventral plate dusky and ending in a long 



slender process, the long anal organ black with a yellow extremity. 



1^ — 2 mm. pleuralis, n. sp. 



67 (66) Hypopygium without bristles. 



68 (69) Wings clear ; angle at forJc variable but never acute. 



$ 9 • Very like pleuralis, but differs in that the pleural bristles are all short ; the 

 wings clearer with the veins darker, the costa rather shorter and the angle at 

 fork usually larger ; the fore tarsi slender in both sexes ; the end of the male 

 abdomen not hairy, but the marginal hairs of the 6lh segment project outwards 

 rather conspicuously, the hypopygium very different, being smaller more 

 globular and glossy black, at least at the base, the subanal body seldom exposed 

 the ventral plate yellow, broad and long and rounded at the end, reaching in 

 the quiescent state to the end of the hypopygium, and the anal organ rather 



