106 THE EARLY STAGES OF TABANID.E 



Tabanus desertus Walker. — South America, British Guiana. The 

 larval and pupal stages have been observed by Bodkin and Cleare in 

 the coast region of British Guiana. Numbers of larvce were found in 

 a damp accumulation of sweepings situated at the end of a drain 

 leading from a large cattle pen. Several of these larvae were secured 

 and kept in the laboratory under frequent observation. Although 

 supplied with a quantity of suitable food the largest larva eventually 

 consumed its companions and pupated. After sixteen days a female 

 Tabanus desertus emerged. The pupal aster (terminal end of the 

 pupa, showing the arrangement of the spines) is figured (Plate 15, 

 Fig. 180, a, h). 



Tabanus ditaniatiis Macquart. — The distribution of this tabanid as 

 given by Austen is wide. 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 1910 it had not been recorded from the northern provinces, when 

 King began his studies on this species. 



The larvae were taken early in March, 1910, in a small water chan- 

 nel, 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 overgrov^^n with a covering of green 

 slime, and when this was cleared away a few larvae could generally 

 be seen on the surface. On stirring up the mud at the bottom and 

 edges of the water more 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 larvae of various sizes were taken on March 9 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 the smaller ones. On March 10 more than a hundred were 

 obtained, and, together with the survivors from the previous day, 

 were divided among three jars (only three being available), two con- 



