l!Kl'nT;T OF THE ENTO^rOLOGICAL SECTION 



121 



dark gvevish-linnvii, clothed with erect black hair, sixth segment also with some l)lack 

 hairs in centre, fifth and sixth segments sometimes more or less infuscatod, especially 

 towards posterior and lateral margins. Squamie isabella-coloured, with buff margins. 

 Halteres ochraceous-buff, tips of knobs cream-coloured. 



Leija : Ooxic olive-grey or smoke-grey, clothed with whitish hair ; rest of front legs 

 black, except proximal halves, or rather less, of tibiaj, which are cream-coloured and 

 clothed with minute, appressed, pale yellowish hairs ; outer side of front femora greyish 

 pollinose, clothed with fine yellowish hair, middle and hind femora fawn-coloured, clothed 

 with pale yellowish hair ; middle and hind tibia- buff, brownish at tips, clothed partly with 

 black and partly with yellowish hair; middle and hind tarsi dark brown, dai-ker towards 

 distal extremities. 



Tahannn limji is allied to an at present undescribed species of Tahanns, of which 

 specimens from Abyssinia are contained in the British Museum collection. The Abyssinian 

 species, however, which agrees with T. kingi in the shape of its frontal callus and in the 

 anterior branch of the third vein being bent at an angle and provided with an appendix, 

 is distinguished from it, at any rate in the female sex, by : — the frontal callus being dark 

 mummy-brown instead of black or clove-brown ; by the much darker colour of the dorsal 

 surface of the body ; by the dorsum of the thorax being distinctly striped, and clothed 

 mainly with black instead of with buff-yellow hair, by the series of pale marks on the 

 dorsum of the abdomen, outside the admedian stripes, taking the form of clearly defined 

 light grey spots, which are distinctly ovate in shape ; and by the ground colour of all 

 the femora, and not merely of those of the front legs, being black. 



Khor Arbat (Fig. 13), the locality in which this seroot occurs, is situated about 

 twenty-two miles N.N.W. of Port Sudan, and consists of a stream of slightly brackish 

 water running in a gorge in the rocky hills. On emerging from the hills into the plain 

 the stream loses itself in the sand. In the autunm, during the brief rainy season, it comes a haunt of 

 down in spate, and is then of considerable size, but in April—the month in which these ^- ^'"■'^' 

 observations were made — it is, except where pools exist, not more than a few inches 

 in depth. The bed of the stream is stony and there is little or no vegetation growing 

 on its banks. 



The female fiy (Plate II., fig. 2) deposits 

 her eggs in a rounded mass on a rock rising 

 sheer from the water (Fig. 14) generally 

 slightly overhanging, and from 6 inches 

 to 15 inches above water level. Eocks chosen 

 for this purpose overhang comparatively 

 deep pools — from 18 inches upwards — in which 

 the water moves but slowly. Such rocks occur 

 only every here and there — in the mile or so 

 of stream searched — only three rocks bearing 

 traces of having been used by this tabanid for 

 pui'poses of ovipositing being found. On one 

 of them were the remains of several hundred 

 egg-masses lining a small crack in the face of 

 the rock from 2 feet to 3^ feet above the 

 water level. As none of the fresh egg-masses 

 found were situated more than 15 inches above water level, these 

 been deposited when that level was higher. Altogether seven fei 



--%1 





tig. 13- — View oC KLor Arbat, Luokiu^ up sii 



Situations 

 chosen for 



old masses had probably ovipositing 

 uales were taken in the 



