86 



somewhat more triangular and elongate in shape ; in addition, these 

 two females also show traces of a patch or streak of yellowish hair 

 in the median line on the second and fifth abdominal segments.* 

 In the Anglo-Egyptian Sudan, to judge from the specimens of 

 the two forms received up to the present time, females with pale 

 hair on head and thorax would appear to be more common than 

 those with golden-yellow hair ; the same variation is seen in females 

 from Uganda, and a female from the Umfuli River, Natal, also has 

 the hair on head and thorax distinctly paler than in other females 

 from the same colony. 



Exclusive of a male and two females of the typical race, from Haith- 

 alhim, near Aden, Arabia, March 20th and 23rd, 1895 (Lt.-Col. 

 Yerbury), the Museum at present possesses sixty-four specimens of 

 T. biguttatits, including fourteen males and fifty females. It will 

 be observed that far more males have been collected than is usually 

 the case where Tabanidae are concerned, and it may also be noted 

 that the species was originally described from a male (from the Cape 

 of Good Hope), whereas the males of Tabanidae generally are so rare 

 in collections that by far the greater number of descriptions have 

 had to be drawn up from the female alone. During the French Ex- 

 pedition to French Congo for the study of Sleeping Sickness, four 

 males of T. biguttatus were taken at Brazzaville, on January 7th and 

 12th, 1907, " at the water's edge, trying to drink on the ground," 

 while a fifth was caught " at a lamp, at 6.30 p.m., during a tornado. "f 

 In the Anglo-Egyptian Sudan Mr. H. H. KingJ has observed that 

 " males appear to be more plentiful than females," and it would be 

 interesting to know the reason for the unusual abundance of males 

 in this species. 



The details as to the localities, etc., of the specimens in the 

 Museum are as follows. 



Cape Colony : Port Elizabeth, 1891 (Dr. H. A. Spencer). Natal : 



* Coloured figures of some of these variations in marking are given by Mr. Harold 

 H. King, in the Third Report of the Wellcome Research Laboratories at the Gordon 

 Memorial College, Khartoum, PI. XXV., figs. 2 and 3, 1909. (Although dated " 1908," 

 on the title-page, this Report was in reality not published until February, 1909). 



f Cf. Surcouf and Roubaud, Bulletin du Museum National d'Histoire Naturelle 

 Annee 1908, No. 5 (Paris, 1908). 



% See below. 



