10 EESTEICTED OCCUEEENCE OE TSETSE. 



drawn attention to the fact that Tsetse may abound on one 

 bank of a stream while there are none on the other. According 

 to Andersson [20], " cattle may be seen grazing securely on one 

 side of a river, whilst the opposite bank swarms with the insect." 

 On one occasion, Livingstone [21], during a two months' sojourn 

 on the Chobe River, preserved his cattle by keeping them on the 

 northern bank, where not a single Tsetse was found, although 

 the south bank, " only fifty yards distant," was " infested " by 

 the fly. A graphic description is given by Mr. C. V. A. Peel 

 [163] of his experience in Somaliland in 1895. Mr. Peel writes : 

 " It is an extraordinary sensation coming into a belt of ' fly.' 

 There may be but a tiny river-bed. On one side of it not a fly 

 will be encountered, but walk a dozen feet and they suddenly 

 come buzzing by one in hundreds." The results of an incursion 

 into the "Fly Country" in Zululand are thus described by 

 Lieut. -Colonel Bruce '• : " On entering ' Fly Country ' one is not 

 left long in ignorance of the presence of the Tsetse. The natives 

 may be seen slapping their naked legs, the dogs bite round, and 

 the horses kick. The Tsetse, however, may be said to be some- 

 what local in its distribution in the ' Fly Country,' being only 

 met with now and then and in few numbers, until you enter 

 some glade or clear space in the thorns, when suddenly the 

 slapping, biting, and kicking go on with tenfold energy, and you 

 can catch thirty or forty flies in a few minutes." 



Just as the worst patches of fly within the limits of a Fly- 

 belt are often sharply defined, so in a large tract infested by 

 Tsetse there may be small areas which for some reason, perhaps 

 owing to their having been cleared of bush, the fly never enters. 

 These spots form veritable harbours of refuge for the traveller 

 who may be compelled to cross the Fly-belt with oxen and 

 horses, since, by travelling at night and taking care to keep the 

 animals within an asylum of this kind during the day, the 

 dangerous zone may be ti*aversed in comparative safety. Thus 

 Selous [121] describes how the forty miles of Tsetse-infested 

 swamp on the western bank of the Loanja River can easily be 

 crossed in three nights, owing to the fact that " there are two 

 islands in the swamp free from ' fly,' to which the oxen can be 

 driven to feed and rest during the day-time." 



The reader who may wish to discover what is known of the 

 actual extent of Fly-belts in a particular region must consult the 

 Bibliography, but should be careful to note the dates to which 



* Cf. Chapter VII., Arpendix A, p. 271. 



