54 



tastes than either of the other two [G. morsitans and G. brevipalpis}. 

 It occurs both in the country favoured by brevipalpis and avoided by 

 morsitans and in that favoured by morsitans and avoided by brevi- 

 palpis, as well as in wooding of its own ; nor do the stray individuals, 

 at any rate, avoid the extremes. Males were taken on the sparsely 

 shaded basalt .... in dry windy weather and with the leaf 

 falling freely, and occasional individuals of both sexes were taken in 



primary forest dominated by Khaya nyasica in full leaf 



" I do not feel that I disentangled its habits sufficiently from those of 

 G. morsitans on the granite-gneiss. Here, in the Brachystegia bush, 



it appeared to occur in every place in which we found morsitans 



It was in great numbers only where morsitans was also numerous 

 namely, at particular vleis and glades ; it was very sparse elsewhere, 

 but less so than morsitans, and both flies (and once brevipalpis, too) 

 were on us or the cattle together. When pallidipes puparia were taken 

 at all, they were under the same log as those of morsitans. 



" West of the Sitatongas, where morsitans does not appear to occur 

 at all, stray individuals of pallidipes were taken in very open bush 

 and in every type of bush but it was never taken even two or three 

 together except in Brachystegia and the less tall of the ' dense 

 secondary ' types. . . . 



".Generally speaking, brevipalpis needs coppice with overwood, 

 while pallidipes prefers coppice without it, but in the right types 

 such as rather poor Brachystegia it can apparently dispense with 

 yet lower growth .... It may possibly best be described as 

 a ' low- wooding fly/ the low wooding varying from mere coppice 

 and bush savannah to poor Brachystegia, etc., though better wooding 

 is to some considerable extent utilised." 



In Zululand, where G. pallidipes is found in Acacia thickets, it would 

 seem that this species is extending its range. According to a recent 

 statement by Mr. R. H. Harris (62a), the extension of the infested area 

 is a secondary result of irregularity in burning off the grass, since 

 tracts which once were open country are gradually becoming covered 

 with A cacia, and consequently favourable to the fly. The germination 

 of the seeds of this thorn is greatly accelerated by heat, and after a bush 

 fire young trees soon appear. If the ground were burnt regularly 

 every year, the seedlings would have but a remote chance of survival, 

 but each year that they escape a fire they become more resistant to 

 it. Neglect of burning for a few years, therefore, causes a gradual 

 transformation from open grass to thorn scrub ; the change occurs 

 almost imperceptibly, but its resultant influence on the numbers of 

 G. pallidipes is very marked (compare Swynnerton's recommendation 

 (145) of regulated, annual, late burning as a method of Tsetse control in 

 North Mossurise, Portuguese East Africa. See pp. 140-141). 



Glossina longipalpis, Wied. " Like other members of the Glossina 

 morsitans group, to which it belongs," writes Austen, " G. longipalpis 

 would appear not to be so closely restricted to the immediate vicinity 

 of water as the species belonging to the Glossina palpalis group of ten, 

 although not invariably, are .... At a certain spot on the 

 Oueme River, in Dahomey, where both G. longipalpis and palpalis 

 occur, the latter species, according to Roubaud, is for the most part 

 confined to the immediate vicinity of the water and to the belt of forest 

 fringing the banks ; G. longipalpis, on the other hand, which is scarcely 



