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AN EXAMINATION OF THE TSETSE PROBLEM IN NORTH MOSSURISE, 



PORTUGUESE EAST AFRICA. 

 By C. F. xM. Swynnerton, F.L.S. 

 (Plates IX-XVII and Map.) 

 CONTENTS. 



I. Introduction . . 

 II. Nature of the Country investigated .. 



III. Wooding of the District analysed in relation to Tsetses 



IV. Factors influencing Leaf- fall . . 



V. Effect of the annual Grass-fires 



VI. Distribution of Rocks, Woodland Types, Food Animals and Fly 

 VII. Umzila's Experiments in Close Settlement 



VIII. The Food of the Fly 



IX. Distributors of the Fly 



X. Effect of the Rinderpest 

 XI. Factors determining the Presence of Tsetses 

 XII. Notes on Habits 



XIII. Proportion of the Sexes 



XIV. Observations on Breeding Habits . . 

 XV. Net Experiments 



XVI. Natural Enemies 

 XVII. Tsetse Concentrations 



XVIII. The Recent Outbreaks of Nagana in Mossurise . . 

 XIX. Clearing Experiments 

 XX. Measures for the Control of Tsetses in Mossurise . . 

 XXI. Discussion of General Methods of Tsetse Control . . 



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I. — ^Introduction. 



In June 1918, I arranged to carry out a preliminary investigation of the habits 

 and distribution of the tsetse-flies in the northern portion of the Mossurise district 

 for a maximum period of three months on the understanding that the Mozambique 

 Company would defray the general expenses of the expedition. 



After a brief stay at Gogoyo's with little success I proceeded to the country east 

 of the Sitatonga Hills. I had found tsetses in considerable numbers there in June 

 1900, and hoped by commencing my work in a well infested area to gain at once 

 a thorough acquaintance with the fly that would stand me in good stead during 

 the rest of my expedition and enable me also to decide quickly on my requirements 

 in the matter of bait and labour. I was fortunate enough to make a number of 

 particularly interesting observations during this first part of my trip, east of the 

 Sitatongas. 



Having found that the large tsetse (Glossina brevipalpis) does not come readily 

 to man or to goats, I applied for cattle to serve as bait. These reached me on 

 (737) 1,000. Wt.P2 154. 3.21. B.&F..Ltd. Gp. 11. a 



