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NOTES ON THE HABITS OF GLOSSIJSA MORSITANS IN 

 NYASALAND AND THE ADJOINING TERRITORIES. 



By Sie ALFEED SHARPE, K.C.M.Q., C.B., 



GOVEBNOR OF THE NyASALAND PROTECTORATE. 



Throughout the Nyasaland Protectorate there are many areas which are 

 infested by Glossina morsitans ; and this species is also to be found in North 

 Eastern Rhodesia, and in German and Portuguese territory bordering on 

 Lake Nyasa. I have been frequently through all these territories during 

 the last 22 years, and know them well. 



From my observations, made very carefully during the last six or eight 

 years, the opinion I have arrived at in every case is that fly-areas have 

 neither diminished nor increased during the time I have known the country. 

 It is impossible to say what are the exact conditions which are suitable in 

 any district for the existence of tsetse-fly. Within a fly-area it does not 

 follow that fly will be found throughout, nor on all days, nor at all seasons. 

 To speak of a " ^y-belt '^ gives a wrong impression. A " fly-area " has more 

 or less definite limits_, and within this area fly may be found, sometimes in 

 one part, sometimes in another.* It is possible to go through a fly-area 

 many miles in extent on some occasions without meeting much fly ; on other 

 occasions they may be found thickly throughout. The season of the year has 

 a great deal to do with this, but there are other causes which it is impossible, 

 as yet, to define. For example, between the settlement of Zomba and the 

 Mlanje Mountains, a distance of about 40 miles, lies an extensive plain. 

 Horses or cattle can be driven across from Zomba during the months of 

 May or June without meeting any fly at all ; later in the year, say October, 

 they wouhl have to pass through about 25 miles of fly. On the advent 

 of the first rains in November there is a noticeable diminution of fly, but 

 they are still found more or less in this particular area until the arrival of 

 the cold weather in April and May. 



My own opinion, which I have expressed on various occasions before now, 

 is that the existence of wild game has very little, if anything, to do with the 



* [The fact that the terms '' fly-belt " and ^^ fly-area " are frequently used as though they 

 were interchangeable is apt to cause confusion. It would be well therefore to restrict the 

 term " fly-belt " to couutry in which Glossina is actually existent ; whereas the word 

 " fly-area " would have a wider sense, signifying a district which is liable to be infested by 

 tsetse, either wholly or in part. Thus evidence as to the alteration of fly-belts would not 

 necessarily be in conflict with the author's view that the limits of fly-areas are stable. — Ed.] 



BULL, ENT, RES. VOL. I. PART 3, OCTOBER I91O. 



