iflii] 175 



32 (33). First costal division nearly three times as long as the 2nd, and the 2nd 



scarcely longer than the 3rd. Stem of halteres hlacli. A large species. 



...nearly 2 mm. mallochi. 



33 (32). First costal division about half as long again as the 2nd., and this nearly 



three times as long as the 3rd. Stem of halteres yellow. A very small 

 species ^-f mill, propinqua. 



34 (29). Costa fully to wing middle or beyond. 



35 (36). Wings colourless. Costa in both sexes incrassated at Jiumeral x-vein. A 



tiny species 2 ram. parva. 



36 (35). Wings distinctly darkened. Costa not incrassated. Moderate sized 



species. 



37 (38). Arista of ^cnusual length. Upper supra-antennal bristles in alignment 



with inner bristles of middle frontal row. First thin vein leaves at 

 fork. Hypopygium large, anal organ long and depressed. 



...1-1^ mm. longiseta. 



38 (37). Arista of usual length. Supra-antennal bristles inside such alignment. 



First long vein ( ^) leaves well on proximal side of fork. Hypopygium 

 very small, anal organ minute 1^ mm. glahrifrons. 



Frons dull. 



Costa moderately long, bat not fully reaching the wing middle. First costal 

 division equal or nearly equal to the 2nd and 3rd together. 



Legs deep black. Hypopygium small f-1 mm. rivalis. 



Legs yellow. Hypopygium large ^f mm. surdifrons. 



Costa very short (i wing length gregaria), or at 7nost not quite f loing length. 



Fi rst costal division at least double the 2n(J and 3rd together. 



A tiny black species with black antenme. Costa only -| the wing length. 



...barely i mm. gregaria. 



A small reddish species with red antennw. Costa nearly f the wing length. 



...f mm. or rather more, ruflfrons. 

 Halteres yellow. 



Frons more or less shining. Costa nearly to wing middle in minor, and 

 less than | wing length in the others. 

 48 (49). Frons very narrow, ^ longer than broad and highly glossy. Inner bristle 

 of lower frontal row considerably below the outer one and placed close 

 to the eye margin l-l4 mm. minor, Zett. 



Frons broader than long. Inner bristles of frontal row in usual position. 



Foretarsi thickened in both sexes. Costal fringe only moderately short. 



...1 mm. or barely, tarsalis. 

 Foretarsi not thickened. 



Cilia on hind tibiie fine and indistinct. Frons distinctly shining. Hal- 

 teres black-stalked. A minute species i mm. angelicse. 



Cilia distinct. Frons only inoderately shining. Halteres yellow-stalked. 

 Not minute species. 



First costal division more than twice as long as 2nd and 3rd together. 

 Costal fringe only moderately short. Upper supra-antennal bristles 

 approaimated, under ones small 1^1^ mm. pygmiea, Zett. 



