265 



SOME OBSERVATIONS ON THE BIONOMICS OF TABANUS 



DIT^NIATUS, MACQUART, AND TABANUS KINGI, 



AUSTEN.* 



By HAEOLD H. KING, 



GOYERNMENT ENTOMOLOGIST, AnGLO-EgTPTIAN ISUDAN, 



Wellcome Tropical Kesearch Laboratories, Khartoum. 



Tabaniis ditaeniatus, Macq. 



The distribution of this Tabanid as given by Austen t is a very wide one. 

 In Africa it occurs from the Transvaal in the south to Egypt in the north, 

 while outside the bounds of Africa it is found in Baluchistan, India, Ceylon, 

 China and Japan. In the Anglo-Egyptian Sudan it occurs fairly commonly 

 in the south, but until this year it had not been recorded from the northern 

 provinces. 



The larvse were taken early in March of this year in a small water 

 channel — locally known as a ' gadwal '' — on the estate belonging to the 

 Sudan Plantation Syndicate Ltd., at Zeidab, Berber Province. The water 

 was for the most part overgrown with a covering of green slime, and if this 

 was cleared away a few larvse could generally be seen on the surface. On 

 stirring up the mud at the bottom and edges of the water more would appear, 

 while if one waited for an hour or so specimens would continue to rise. They 

 were apparently living in the mud at the bottom of the pools and coming 

 periodically to the surface to breathe. They could be seen rising to the 

 surface by a lashing motion, and if left undisturbed would, after a few 

 seconds, sink out of sight again. 



Some forty odd larvse of various sizes were taken on March 9th and placed 

 in a jar containing water, slime and hollow grass stems ; most of these had 

 disappeared by the next morning, the larger ones having devoured their 

 smaller brethren. On March 10th more than a hundred were secured, and, 

 together with the survivors from the previous day, divided among three jars 

 (only three being available), two containing wet mud, and the third water 

 with hollow grass stems and other debris. Earthworms were provided as 

 food, but were not taken very readily ; the larvae seemed to prefer to eat each 

 other. They were brought to Khartoum on March 11th, and the following 

 morning each of the thirty-three which were still living was placed in a 

 separate jar containing clean river sand and water. They fed freely on tiny 

 earthworms, but their numbers steadily decreased until about April 16th, 



* A record of research work carried out in the Wellcome Tropical Kesearch Laboratories 

 aud published by permission of the Director of Educatiou, Sudan Government. 



t Austen, E. E., African Blood-sucking- Flies, pp. 118, 119. 

 BULL. ENT. RES. VOL. 1. PAllT 4, DECEMBER I9IO. ' Y 



