234 Mr. J. R. Malloch on Exotic Muscaridae. 



Subfamily Ccenosiin^. 



Genus Brevicosta, nov. 



Generic characters. — Closely resembles Cosnosia, Meigen. 

 Differs in having the arista moderately long-haired, ocellar 

 bristles not longer than the postvertical pair; fore tibia 

 unarmed at middle, mid-tibia unarmed at middle on 

 anterior surface, hind tibia with two antero-dorsal and two 

 postero-dorsal bristles, and the costal vein not extending 

 beyond apex of third vein and with short black setultfi to 

 beyond apex of second vein. 



Genotype, the following species. 



Brevicosta africana, sp, n. 



Female. — Head black, densely whitish pruinescent, the 

 interfrontalia, when seen from in front, less densely 

 pruinescent than orbits and frontal triangle ; antennae 

 yellowish, second segment largely brown ; palpi yellowish, 

 infuscated apically. Thorax black, densely grey pruinescent, 

 not distinctly vittate, but darker along the lines of dorso- 

 centrals. Abdomen black, densely grey pruinescent, with 

 three black spots on each tergite, the median spots forming 

 an almost complete vitta ; apices of tergites 2 to 4 narrowly, 

 of 5 broadly yellowish. Legs entirely yellowish. Wings 

 clear. Calyptree brownish yellow. Halteres yellow. 



Frons at vertex less than one-fourth of the head-width, 

 widened anteriorly ; frontal triangle narrow, extending to 

 anterior margin of frons ; arista with its longest hairs about 

 as long as width of third antennal segment, the latter 

 extending about two-thirds of the way to mouth-margin. 

 Acrostichals in two scries ; dorso-centrals 1:3; lower 

 stigmatal bristle minute or absent. Mid-tibia with one 

 posterior bristle; hind tibia with one antero-veutral, two 

 antero-dorsal, and two postero-dorsal bristles, the apical one 

 of the two antero-dorsal bristles very long. Veins 3 and 4 

 divergent apically. Lower calyptra little larger than upper. 



Length 3 mm. 



Type, Zungeru, Northern Nigeria, xi. I&IO (Dr. J. W. 

 Scott-Macfie). 



