SOME BLOOD-SUCKING AND OTHER DIPTEEA FKOM THE ANGLO-EGYPTIAN SUDAN 



57 



Tabunus tlioracbms, Pal. de Beauv., a species which is common in Uganda, and may 

 therefore be expected to occur iu the Bahr-El-Grhazal, is closely allied to T. par, with which it 

 agrees in the colouration of the body, and in the narrowness of the front. T. thoracinus 

 may, however, be distinguished by its generally larger size (the average length of the 

 female is 13 mm.) by its brownish wings, and especially by the front tarsi and tips of the 

 front tibiae being dark brown. Tahanus jMr and T. thoracinus belong to a group of species 

 (two or three of which, found in the Congo Free State and Abyssinia, have yet to be 

 described) characterised by the yellow or ochraceous colour of the body, and by the 

 narrowness of the front in the female sex. No males of these species are at present available 

 for comparison, but since the eyes in the females are sparsely covered with minute hairs 

 (often difficult to see when the specimens are not in perfect condition), while there is 

 no trace of an ocellar tubercle, it is clear that, if thought advisable, the species may be 

 assigned to the sub-genus Ali/loftis, Osten Sacken. 



Tahanus ditceniatus, Macq. 

 (Fig. 22) 



1 (1838), p. 126 ; Bezzi, Ann. Tabanus 



dita^niatus 



Tahanus ditceniatus (sic), Macquart, Dipt. Exot., I. 

 Mus. Civ. di Storia Naturale di Genova, Ser. 2a, XII. (XXXII.) (1892), p. 184. 



Atijlotus nii/romaculatuv, Kicurdo, Ann. Mag. Nat. Hist., Ser. 7, VI. (1900), p. 165 



(N.B. — This synonymy is^new.) 



The following is a description of 

 the female of this species. — -^ (11 

 specimens), length 11 to 14 mm. 



Greyish-yellow ; a pair of con- 

 spicuous shinimj /'lack (hits on f/ic front ; 

 ahdotuen with three longitudinal hlackish 

 or hrownish stripes on the centre one of 

 which is a i/cllowish pollinosc stripe. 



Head whitish (vertex buff) ; the 

 shining black dots on the front one 

 above the other, the lower just above 

 the angles of the eyes, the upper about 



the width of the front higher than the """" f.g. 22.-Tabanus d.t^n.atus, Macq. ? 



former; antenna3 ochraceous-buff. first Natal to the Bahr-Ei-ohazai. 



Head and thorax yellowish; abdomen ochraceous-bufF with dark brown, 

 joint paler" underside of head clothed somewhat serrate longitudinal stHpes ; antenna yellow ; legs yellow ; front 

 ^' i ' tarsi entirely, middle and hind tarsi, except at base, brown. 



with whitisli hair ; palpi white or 



yellowish white, clothed on outside with yellowish interspersed with minute black hairs ; eyes 



in dried specimens usually with a narrow dark transverse band on a level with lower dot on front. 



Thora-c : dorsum blackish, yellowish or greyish poUinose and clothed with short golden 

 yellow hair. 



Abdomen ochraceous-buff, with a broad blackish or brownish median stripe (sometimes 

 with slightly serrate edges) , and a similar narrow stripe on each side ; the lateral stripes are 

 not in contact ^^^th the actual lateral margins of the abdomen, and all three stripes meet 

 together at the tip; in tlie midille line, superimposed on the median stripe, is a yellowish 

 pollinose stripe clothed with short golden yellow hair; this lighter stripe is really composed 

 of a series of triangles with their apices truncated and directed forwards ; the dark stripes are 



