272 HABITS OF TSETSE-FLIES. 



tion 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. 



" The Tsetse has a direct flight, flopping, if I may use the 

 term, suddenly on the animal attacked, and is very pertinacious. 

 It affects in horses the legs, especially in the region of the fetlock, 

 and on being detached from its position by the vigorous kick the 

 horse gives, will only i-ise a few inches and again settle near the 

 same spot. After the initial prick there is no irritation, and the 

 animal will stand quietly while the fly has its feed. 



" In man the burying of the proboscis in the skin is accom- 

 panied by a sharp prick, which draws one's attention suddenly to 

 the spot ; but the pain is, as a rule, trivial, and the subsequent 

 redness and irritation very slight indeed — in fact, less than that 

 caused by the mosquito. 



" But under some circumstances the Tsetse may become 

 almost unbearable. In January, when camping in the Fly 

 Country close to the River Mkusi, these flies were very numerous, 

 and in conjunction with the intense heat — the thermometer often 

 registering 100*^ F. to lOG*' F. in the shade of a double tent — 

 almost drove one mad. One can easily imagine the effect of the 

 constant worrying of these pests by day, followed by mosquitoes 

 at night, and minute ticks at all times, on any nervous system 

 except the most stable. The horses fared no better, and could often 

 be seen trotting about trying to escape from their tormentors. 



" About sunset seemed a favourite feeding-time, and then the 

 poor creatures would be surrounded by a perfect cloud of the 

 flies, while some hundreds of them would be settled on them at 

 the same moment. 



" I have not noticed them biting during the night, but that 

 excellent sportman and observer Selous states that by moonlight 

 ill some places they bite just as furiously as in the daytime. 



" The fly makes a loud buzzing sound when flying, but after 

 its feed and at rest it emits a peculiar sharp, shrill note, probably 

 caused by an action of the wings. 



" In horses, dogs, and cattle I have usually failed to find any 

 swelling or symptoms of irritation following the bite, but on 

 sevex'al occasions a well-marked soft swelling under the skin of 

 the part bitten, as large as a hazel nut, was observed, and this 

 persisted for some time. 



" The Tsetse is not at all easy to catch with the hand, 

 especially during the day, being nimble and quick of movement, 

 but at early morning or sunset they become more lethargic, and 

 are then more readily secured. When I wanted living specimens 

 for any purpose I provided myself with a butterfly-net, with 

 which it is ea?;y enough to catch them unhurt. 



