176 ERiJEST E. AtrSXEN—TWO NEW SPECIES OF grey on front margin, and with a grey stripe on each side, a narrow grey median line extending from front margin to a little beyond transverse suture, and a complete grey stripe between median line and each lateral stripe ; viewed from the side, an ill-defined dark brown horizontal mark, partly clothed with black hair, is seen extending from base of wing towards humeral callus ; pleuraj and pectus light grey, and clothed with white hair ; scutellum clothed above with appressed, yellowish hair. Ahdomen : the series of truncate triangles forming the median dorsal stripe extends from the base of the abdomen to the hind margin of the fifth segment, and the triangles, like the spots, are clothed with appressed yellowish hair ; the paired light grey spots are present on the first six segments, and are disconnected : spots on first segment connected with grey covering of basal angles, sj)ots on following segments usually connected, more or less distinctly with hind margins ; posterior angles of first six segments, and extreme hind margins of second to sixth segments inclusive cream-buflP ; lateral margins of first four segments grey, clothed, as also are posterior angles of first six segments, with whitish hair ; venter grey, first four segments and posterior angles of fifth clothed with minute, appressed, whitish hairs, sixth and seventh segments and median portion of fifth clothed with black hair ; a broad slaty-black median stripe extending from front margin of second to hind border of fifth segment ; sixth and seventh segments (except hind border of sixth) black ; hind borders of second to sixth segments inclusive cream-coloured. Wings hyaline, veins dark brown ; sti(jma elongate, dark brown and conspicuous ; hase of anterior branch of third longitudinal vein without an appendix. Halteres : knob cream-coloured, dark brown at base ; stalk cream-buft', dark brown at distal extremity. Legs slate-grey, tarsi and distal extremities of tibife clove-brown or black, front half of proximal twothirds of front tibia3 cream-coloured, corresponding portion of middle tibiaj and proximal two-thirds of first joint of middle tarsi cream-bufF, extreme base of first joint of hind tarsi also cream-buflP, coxte, femora, and front surfaces of tibiaa (except distal extremities) clothed with whitish hair.

Anglo-Egyptian Sudan, and Somaliland : type and two other specimens from Khor Arbat, Bed Sea Hills, Anglo-Egyptian Sudan, 9, 10. IX. 1909 {H. H. King) ; a fourth specimen from Karora, Red Sea Province, Anglo-Egyptian Sudan (near the frontier of Eritraea), February, 1909 (forwarded by Mr. H. H. King) ; a fifth specimen from Heile Madow, R. Webi, Somaliland, 19. XI. 1908 (Dr. R. E. Drake-Brochnan). At Karora, according to information supplied by Mr. King, Tahanus mordax and T. leucostomus, Lw., which it closely resembles, are termed " lamas " by the natives, by whom the bites of both species, as also those of Pangonia magrcttii, Bezzi, are said to be fatal to camels.

The resemblance between Tahanus mordax and T. leucostomus Lw.~, is so close as to suggest that the former may ultimately prove to be a form of the * Syn. T. iMuseiinia, Jkiiu.— T. leucostomus, Lw., the type of which was obtained on the Kuisip River, German S.-W. Africa, also occurs in Somaliland and Abyssinia, while a female of this species, taken at Karora, Red Sea Province, Anglo-Egyptian Sudan, at the same time as the female of T. mordax referred to above, was presented to the British Museum (Natural History) with the latter, by Mr. H. H. King.