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SwYXNEKTOx (C. F. M.)- An Examination of the Tsetse Problem in 

 North Mossurise, Portuguese East Africa.— L*////. Ent. Res., 

 London, xi, pt. 4, March 1921, pp. 315-386, 9 plates, 1 map. 



The important investigations here described, which should be con- 

 sulted in the original, were concerned chiefly with Glossina morsitans, 

 G. pallidipes and G. brevipalpis, though G. austeni is also noticed. 

 The Mossurise fly problem is of particular interest, not only because of 

 the presence in the district of so many different species of Glossina 

 and the very varied conditions of vegetation, elevation, rock-forma- 

 tion, etc., that affect them, but also because part of the area was, 

 under the Zulu domination, the scene of an artificially directed scheme 

 of settlement that resulted in the banishment of tsetse-flies. This 

 indicates that settlement, properly planned, is itself capable of clearing 

 the country affected of the two flies here concerned — G. hrevipalpis 

 and G. pallidipes. 



Other points to which particular attention was given were an 

 analysis of the vegetation, and of the distribution and local behaviour 

 of the various woodland types. Each species of Glossina is dependent 

 on particular but different shade conditions, and a knowledge of the 

 types of woodland that provide these conditions and their response 

 to seasonal and other influences, burning, etc., is essential for an}' 

 clearing operations that may be undertaken in the future. A very 

 large amount of information was also collected concerning the habits 

 of the various tsetse-flies, the types and distribution of the animals 

 of^' which they feed, the methods and extent of their spread, their 

 natural enemies, etc. 



Experiments were made in clearing the undergrowth in various 

 ways, and its effect on the several species of Glossina. Cattle were 

 taken successfully through a fly belt when the bush on each side of 

 the road had been cleared, and also by means of decoy animals so 

 placed with regard to the more valuable ones that the latter w'ere 

 not attacked. 



But perhaps the most important of the recommendations made 

 as a result of these investigations concerns the particular form of 

 clearing produced by regulated burning. The Zulus used to regulate 

 burning for hunting purposes, but under European administration 

 everyone burns when he pleases. Irregular burning means that when 

 the later fires take place the areas burned earlier are already becoming 

 fit for the reception of the fly. A still worse effect is the encourage- 

 ment given by too early burning to the wooding, and particularly 

 to the formation of the thickets on which G. brevipalpis rather specially 

 depends. Late burning, on the other hand, finds the grass and fallen 

 leaves at their driest and achieves much actual destruction of young 

 growth, and a temporary destruction of much high shade as well, at 

 a hot, dry time that must be relatively critical for the fly. Late burning 

 is not an emergency measure, but would have to be kept up annually. 

 Apart from varying grass conditions, its effect should show first and 

 chiefly in relation to G. brevipalpis, and, in the area where it depends 

 mainly on coppice, G. pallidipes. Its effect in relation to G. morsitans 

 is less certain, as that fly and G. pallidipes in the same wooding appear 

 to be independent of undergrowth ; but the process will assuredly 

 tell, as the established fire-resisting trees pass maturity with nothing 

 to replace them. 



Close settlement, as mentioned above, involving effective clearing, 

 will protect itself, and under the Zulus close settlement in the form 



