•TLY-BELTS" AND THEIE EXTENT. 9 



encounter with swarms of Tsetse on the Kapotche River, their 

 furious onslaughts rendering it impossible to take a meal, or 

 even to remain seated. Sir Harry Johnston [145] states that 

 in British Central Africa, " on the Mwanza River, an affluent of 

 the Shire nearly opj^osite to the Katunga, the Tsetse are so 

 numerous that the only domestic animals which can be kept by 

 the natives are fowls." Lastly, to pass for a moment to Somali- 

 land, Mr. C. V. A. Peel [163] who met with Tsetse {Glossina 

 longipennis, Corti) in that country in 1895, mentions an occasion 

 when his camels on returning to camp in the evening " were 

 followed by a perfect swarm of Tsetse-fly." 



As stated at the commencement of the pre- 



theii' extent • ceding section a tract of country in which the 



distribution and Tsetse occurs is termed a "Fly-belt."* Al- 



limits of Tsetse au i i ii, e • • j.i 



within these areas, though along the courses of rivers, or m the 



low countiy bordering a coast line, fly-belts 

 may extend for hundreds of miles, varying greatly in width 

 according to the nature of the country, it does not follow that 

 Tsetse-flies are to be met with at every point throughout the 

 extent of the belt. More usually they are confined to particular 

 patches of forest or bush, the area of which may be quite small. | 

 Thus, according to Raines [55], "the fly is extremely local, and 

 extensive districts in which it prevails may be passed through 

 by the aid of guides, who know the ' patches ' of fly, just as a 

 pilot knows the shoals of an estuary." Mr. J. AV. P. McLellan, 

 writing of the Jubaland Province of the East Africa Protect- 

 orate, states that " in many places the areas in which fly 

 exist are quite small, possibly only a few hundred yards in 

 extent. . . ." f Again, Mr. F. J. Jackson in 1887 found Tsetse 

 "in great numbers in a small patch of thick bush, about a mile 

 and a half long and three-quarters of a mile wide," § near 

 Taveita ; later he met with it "in considerable numbers in a 

 narrow belt of forest, not more than a mile wide, between 

 Mkonumbi and Witu." § The limits of these patches or areas, 

 as of the fly-belts themselves, are doubtless defined more or less 

 by the physical characters already alluded to ; but, nevertheless, 

 it is often difficult to account for them. Various writers have 



* Often spoken of shortly as " the Fly," just as the term "Fly " is also 

 used in the special sense of "Tsetse." 



f These small fly-infested areas are themselves termed belts by some 

 writers. 



X Chapter VII., Appendix C, p. 294. 



§ Ibid, p. 296. 



