On the BombyJ it'll F<IUHH of South Africa (Dipt era). 133 



1 (8). Apical cross-vein of the discoidal cell straight; head, .antennae and 



palpi entirely black ; discal cross-vein placed near the base of the 

 discoidal cell, win^s never fenestrate. 



2 (5). "Wing-s entin-ly hyaline, only narrowly yellowish or blackish at the 



base and in the subcostal cell. 

 i (4). Wings with pale yellowish base; the attenuated part of the third 



antenna! joint rather thick . . . leucoproctus, Loew. 



4 (3). Wing-s with blackish base and blackish subcostal cell ; styliform part 



of the third antennal joint very thin . . . linea, Loew. 



") (2). Wings with a rather extended brown or blackish pattern, filling 1 out 



the base of the second basal cell and the base of the anal cell. 



6 (7). First posterior cell distinctly narrowed at end; discal cross-vein 



placed near the middle of the discoidal cell ; third posterior cell long 

 and with an acute base . . . ?>,-ni>tns, Loew. 



7 (6). First posterior cell not narrowed at end; discal cross-vein near the 



base of the discoidal cell; third posterior cell shorter and with an 

 obtuse base ....... lugens, Loew. 



8 (1). Apical cross-vein of the discoidal cell S -shaped ; head, antennae and 



palpi mainly or wholly yellow ; discal cross-vein on or after the 

 middle of the discoidal cell ; wings fenestrate, viz. with hyaline spots 

 on cross-veins and bifurcations. 



9 (10). Two submarginal cells only, as usual ; wings very broadly yellowish 



at base, the brown fenestrate pattern being reduced to a less defined, 

 not broad band on the middle of the wing ; species of small size and 

 of a paler colour .... calochromatus, sp. nov. 



10 (9). Three submarginal cells ; wings with more than the basal half filled 

 with a brown extended pattern, and very narrowly or not at all 

 yellowish at the base ; species of large size and darker colour. 



ternarius, BezzL 



THYRIDANTHRAX FLAMMIGER, Walker (1849). 



Distinct by the conical face, the short third posterior cell, the 

 infuscated costal cell and the middle cross-vein marginated with 

 fuscous. 



Of this West African species of the group afer there are 2 speci- 

 mens from M'Fougosi, Zululand (W. E. Jones). 



THYRIDANTHRAX LEUCOPROCTUS, Loew (1860). 



A small species, distinct owing to its wholly hyaline wings, which are 

 only a little pale yellowish near the base. 



Originally described from the Cape, and not recorded subsequently. 



A single female specimen from Klerksdorp, Transvaal, December, 

 1890. 



In the first example the contact between the third posterior and the 

 discoidal cell is rather straight and about twice as long as that 



