ADAMS : DIPTERA AFRICANA. 199 



shining; front and middle knees and middle tarsi, except last 

 two joints, yellowish ; all femora and front and middle tibiae 

 ciliated with bristly hairs, the hind tibiir with the usual apical 

 spine and two subapical bristles ; hind metatarsi swollen a? 

 usual, and scarcely longer than following joint. Wings hya- 

 line, tinged with a faint yellowish brown ; costa distinctly cili- 

 ated as far as the tip of the first vein ; small cross-vein a little 

 beyond the tip of the first vein, last section of fourth vein a 

 fifth longer than the penultimate. Length, 2.7 mm. 



Borborus gravis, n. sp. 



Male and female : Front broader than one eye, triangle reach- 

 ing anterior margin, and with the frontal orbits grayish poUinose, 

 remainder of front opaque black, with a shining line on the 

 anterior part, just laterad of triangle, and bearing a row of short 

 bristly hairs, also a row of gray orbits ; two fronto-orbitals, two 

 verticals, and a pair of ocellar bristles present. Face, cheeks 

 and occiput black, subshiuing, grayish pollinose ; former con- 

 cave in profile, with a low median carina, vibrissse strong. 

 Mouth-parts black. Antennae black, third joint subglobular, 

 sometimes with a reddish tinge on inner side at base, arista 

 microscopically pubescent. Thorax from posterior view sub- 

 shining, from front view opaque, brownish pollinose, with two 

 submedian grayish lines ; one humeral, two posthumeral, one 

 presutural, one supraalar and three dorso-central bristles on 

 each side, the small bristly hairs arranged in six rows ; scutel- 

 lum with four bristles ; halteres yellow. Abdomen subopaque 

 black, grayish pollinose, second segment elongate. Legs black, 

 anterior and middle knees and middle tarsi, except the last two 

 joints, yellowish ; femora and tibiae armed with bristles, middle 

 tibiae with one near middle and three near apex, hind tibice with 

 two strong bristles apically beside the curved apical spine. 

 Wings hyaline, costa slightly thickened just beyond tip of first 

 vein, and distinctly ciliated in front of it, small cross-vein a 

 little distad to tip of first vein, and last section of fourth vein 

 but little longer than preceding section. Length, 2.1 mm. 



Four specimens ; February. 



