48 



appear to be confined to the coast belt in British East Africa [Kenya . 



Colony], where it evidently has a fairly wide distribution , 



Up to the present it has not been captured at a greater elevation than 

 about 1,500ft. above sea-level." G. austeni, which, according to 

 Newstead appears to be especially harmful to stock, likewise occuis 

 in Tanganyika Territory and Portuguese East Africa. 



Glossina morsitans, Westw. " As indicated by the term ' fly-belt/ ' 

 wrote Austen (3) in 1911, "originally applied to G. morsitans, this 

 species is usually confined to quite definite tracts, often of very limited 

 extent. Within these ' belts ' the fly sometimes attacks human 

 intruders in such numbers as to have been compared to a swarm of 

 bees. Cover, usually in the shape of large trees with thick under- 

 .growth, open thickets, or scattered, shady trees, is essential to the 

 existence of G. morsitans, which, like other species of Tsetse, is never 

 found on the open, sun-scorched veld. 1 Authorities like Mr. F. C. 

 Selous, Sir John Kirk, and others (whose experiences, it should be 

 pointed out, relate to the period before the buffalo was driven north- 

 ward, or almost exterminated by rinderpest), write of G. morsitans 

 occurring in swarms on the banks and ' along the water's edge ' of the 

 -Zambesi, Chobe, Rovuma and other rivers. Recent observers, on 

 the other hand, such as Dr. L. Sander (in German East Africa), Sir 

 Alfred Sharpe (in Nyasaland), and Mr. S. A. Neave (on the south-west 

 shore of Lake Nyasa, and on the Luangwa River in north-eastern 

 Rhodesia), lay stress on the fact that, in their experience, G. morsitans 

 evinces a dislike to, rather than a preference for, the immediate vicinity 

 of water, whether river or lake, and is not infrequently met with at 

 a considerable distance (half a mile or so) from any water. 2 In this 

 connection it is not uninteresting to remember that the original 

 specimens of G. morsitans, found by Vardon and Oswell in 1845, were 

 obtained on the Siloquana Hills in the Northern Transvaal, between the 

 Magalaqueen or Nylstroom River and the Limpopo. Glossina 

 morsitans, indeed, is by no means confined to low-lying districts. 

 Some three years ago Mr. E. A. Copeman, at that time District Com- 

 missioner at Kasempa, forwarded to the [British] Museum a number 

 of specimens of this species taken by him in January 1908, on the 

 Congo-Zambesi watershed, Kasempa district, North-Western Rhodesia, 

 at an altitude of from 5,000 to 5,500 ft. In Nyasaland, however, 



1 This refers more especially to conditions such as those in the Transvaal. 

 Dr. S. A. Neave (103), writing in 1912 of his " own personal experience and 

 observations of Glossina morsitans " in Eastern Tropical Africa, says : " I am of 

 opinion that among the essential factors which determine the distribution of this 

 species, are a combination of the presence of such vegetation as will provide 

 moderate but not excessive cover, coupled with a hot and mpderately or even 



very dry climate I have on several occasions, particularly in 



Northern Rhodesia, noted that when the grass is long (not less than four feet) 

 G. morsitans is inclined to be more numerous in grassy areas of limited size than 

 in the woodland or bush-covered country surrounding them. I have more than 

 once seen this species swarming in long grass on plains of some size, from half a 



mile to a mile or more from the line of bush at the edge In large 



short -grass plains, such as those to the east of Lake Bangweolo, this fly does not 

 occur, nor from the paucity of the cover would it be expected to do so. G. morsitans 

 also appears to avoid the other extreme, viz., dense forests where the atmosphere 

 is cool and damp." 



2 Writing in 1912 with reference to G. morsitans, Dr. S. A. Neave (103) remarks : 

 " Compared with most species of Glossina, the complete independence of water 

 exhibited by this species is remarkable. In the Luangwa Valley I have seen it 

 swarming, in intensely hot weather, at least five miles from any known water. 

 Indeed, the drier the atmosphere the greater seems to be the activity of this 

 -fly." 



