59 



high, dark secondary wooding on the Sitatonga base, excepting at 

 the occasional thickets, suggests that extra shade may not be the only 

 advantage gained from thickets. Protection from drying winds, 

 additional protection from the eyes of enemies (such as the thickets 

 very definitely afford) and some advantage to the pupae are the 

 three that occur to me, but I am convinced that shade is the chief 

 consideration." 



Glossina medicorum, Austen. Of this species we still know nothing 

 more than we did eleven years ago, when Austen (3) wrote that " it 

 would seem that it sometimes moves about after dark, at any rate, 

 when attracted by light " 



Glossina longipennis, Corti. Few observations have yet been made 

 upon this Tsetse-fly, which, as has already been stated, is in the habit 

 of entering carriages on the Uganda Railway at night, in company 

 with G. brevipalpis and G. pallidipes. Dr. S. A. Neave, to whose 

 statements on the subject we have previously referred, writes (103) : 

 " This is a desert-haunting species, confined, so far as at present known, 

 to North-Eastern Africa. It is widely spread over the lower-lying 

 and drier regions to the east and north in the British East Africa 

 Protectorate [Kenya Colony], and will very probably be found extending 

 into the Uganda Protectorate in the country to the south-west and 

 west of Lake Rudolph. It appears to be absent from the sea-coast, 

 where the climate is probably too humid for it. It would seem to 

 be entirely independent of water, and indeed rather to avoid it. 1 I 

 found it most striking, when travelling from station to station on the 

 railway between Voi and Makindu, to find numbers of this species 

 in the dry, semi-desert, thorn-scrub 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." 



In elevated districts G. longipennis is met with between the rivers 

 and not upon their banks (Chalmers and King) . 



To conclude the foregoing sketch of what is known as to the habitats 

 of the different species of Tsetse-flies, which, though brief, is necessarily 

 somewhat diffuse owing to divergences of view among the authorities 

 cited, we reproduce the following " classification according to environ- 

 ment," drawn up by Dr. S. A. Neave (103). Although restricted 

 by its author to East African species of Glossina, it seems to us 

 that the scheme might also be made to include in a general way 

 the entire genus. 



"A. Requiring a great degree of atmospheric humidity : 

 A.I. 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.I. 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. 



1 Curiously enough, in the Southern Masai Reserve, Kenya Colony, in 1917-18, 

 G. longipennis was found by Anderson (la) unexpectedly abundant on moist, 

 swampy flats and on the bank of a river. 



