﻿INSECTS OF EASTERN TROPICAL AFRICA. 309 



country between the rivers, while on the river banks it was replaced by 

 G. brevipalpis. 



Like the other large species of Glossina it is chiefly on the wing and inclined 

 to feed in the early morning and late evening. It is probably the species which 

 most frequently enters the railway carriages on the Uganda Railway at night, 

 that being the time when the principal trains traverse the region between Voi 

 and Makindu. 



Glossina fusca, Walk. 



This "West African species of tsetse enters the region under discussion only on 

 the western boundaries of Uganda. It is not uncommon in the forests of Toro 

 and the Semliki Valley, and is also reported from the Budongo forest, Unyoro, 

 though I did not meet with it there myself. From a limited experience of this 

 insect it would appear to be essentially a dense forest, rather than a riverine, 

 species, and evidently delights in very deep shade. Though occurring in many 

 places with Glossina pcdpalis, the distribution of the two species is by no means 

 coincident, since G. fusca seems to be able to exist at considerably greater 

 elevations and in much cooler localities. In Uganda the limit for this species 

 seems to be about 4,500 feet, as compared with rather under 4,000 feet for 

 G, pcdpalis in the same region. It is of course also numerous at much lower 

 elevations, e.g., the forested portions of the Semliki Valley at under 2,500 feet. 



It seems to feed principally in the early morning and late evening and shows a 

 decided preference for animals, as compared with man. 



The above notes on the habits of the East African species of Glossina may 

 perhaps best be summarised by the following classification according to environ- 

 ment : — 



A. Requiring a great degree of atmospheric humidity : — 



A. 1. Requiring a high temperature. G. palpalis, R. D. 



A. 2. Not requiring a high temperature. G. fusca, Walk. 



B. Requiring only a moderate degree of humidity : — 



B. 1. Requiring comparatively little cover. G. pallidipes, Aust. 



B. 2. Requiring fairly heavy timber and bush. G. brevipalpis* Newst. 

 B. 3„ Requiring more or less dense forest. G. austeni, Newst. 



C. Independent of water and most active in a dry atmosphere. G. morsitans. 



Westw., and G. longipennis, Corti. 

 The three large species, G. brevipalpis, G. longipennis and G. fusca, may also 

 be separated from the others by their being mainly crepuscular or nocturnal in 

 their habits, instead of being most active in sunshine. 



Genus Stomoxys, Geoffr. 



The flies of this genus are, after Glossina, the principal biting flies in Africa 

 belonging to the Muscidae. In my experience, they only exceptionally bite 

 man, exhibiting a marked preference for other animals, particularly domestic 

 ones. They are common nearly all over Eastern Africa in the neighbourhood 

 of townships and human habitations where any appreciable number of domestic 

 animals are kept. Though I have exceptionally taken the flies of this genus in 

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