310 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.xxi. 



hairs, as are also the gray triangles, hairs on the brown portion of the 

 abdomen black; venter yellowish brown, the hind niaigins of the seg- 

 ments yellow. Legs bhick, the tibiae, with the exception of the apices 

 of the front orfies, yellow, llalteres yellowish brown. Wings yellow- 

 ish gray, the centers of the (;ells nsnally hyaline, lirst posterior cell 

 slightly narrowed at its apex, the anterior branch of the third vein 

 bears a long appendage near the base, veins brown, stigma yellow; 

 npper calypteres white, the lower ones yellowish brown. 



Length, 22 to 2S mm. Eight males (No. 720) and ten females (Nos. 

 710 and 722). 



Type.— Bo. 397;{, U.S.N.M. 



TABANUS TRIGEMINUS, new species. 



Female: Ditfers from the above description of truj o tin s ou\y im fol- 

 lows: Head above the antennae yellowish gray prninose, antennae on 

 the lirst two joints black, the tooth of the third unnsually small; hairs 

 of the occipnt, on the nnder side of the head and on the pleura, white. 

 Abdomen somewhat polished, black, the narrow posterior margins of 

 the segments yellow, tirst segment thinly grayish-black pruinose, the 

 middle of the dorsum opaque, light gray pruinose; segment 2 opacpie, 

 light gray pruinose except four large spots of the black ground color 

 in a transverse row; segments 3 to (I opa(iue, light giay i)ruinose in the 

 middle, on the posterior margin and on the sides, the gray in the 

 middle forming a triangle on each segment, and on the third usually 

 expanded each side in the form of a small subdorsal triangle, the hairs 

 of the gray portions light yellow; venter black, wholly light gray prui- 

 nose or brown pruinose in the middle, the sides broadly light gray 

 pruinose. Legs black, the tibiae, except the apices, yellowish white. 

 Halteres brown, ,the knobs yellow. Wings hyaline, the stigma yellow- 

 ish, tirst posterior cell narrower or only slightly broader at the apex 

 than at the base, anterior branch of the third vein not appendiculate. 

 Length, 17 to 18 nun. Six specimens (No. 721). 



Type.— Bo. ai)74, U.S.N.M. 



TABANUS TENEBROSUS, new species. 



Female: Differs from /r/Vyoww,s as follows: Head above the antennae 

 yellowish-gray pruinose, tooth of the third antennal joint very small, 

 hairs of occiput, of under side of the head and on the pleura, white. 

 Abdomen opaciue, black, sometimes a. reddish spot on sides of the sec- 

 ond segment, wholly grayish pruinose, the median triangles, posterior 

 and lateral margins of segments 2 to G, a lighter gray than the 

 remainder of the abdomen; the darker markings consist principally of 

 l)airs of spots bordering the median triangles; venter black, brownish- 

 gray pruinose in the middle, the sides a lighter gray. Wings hyaline, 

 stigma pale yellowish. Length, 18 to 20 mm. Four specimens (No. 

 721). 



Type.— Bo. a!)7r>, L.S.N.M. 



