PREFACE 



In connection with the economic development of the vast potential 

 resources of Tropical and Subtropical Africa, one of the most important 

 problems to be solved is the control of the commoner species of 

 Tsetse-flies. 



Their menace to human life as carriers of sleeping sickness is very 

 grave, and requires to be met ; but apart from this their serious 

 adverse effect on the agricultural development of very large areas of 

 fertile land is of even greater immediate importance. 



The presence of these insects, most of which transmit various 

 forms of trypanosomiasis, a disease that is fatal to domestic animals, 

 constitutes at present an insuperable bar to their use in these regions. 



These flies are widely distributed throughout Tropical Africa, and 

 when it is realised that probably one-half of Tanganyika Territory 

 is infested by one or other species, and that in Northern Rhodesia 

 and Sierra Leone nearly three-fourths of these countries are similarly 

 infested, it becomes clear that investigations directed towards the 

 discovery of practical means of extirpating this scourge are urgently 

 needed. 



It is perhaps of interest to recall that the earlier Portuguese explorers 

 were continually baulked in their endeavours to settle on the healthier 

 inland plateaux of East Africa, owing to the fact that their transport 

 animals were inevitably killed off by Tsetse-flies : and, indeed, but 

 for the presence of these insects, the subsequent history of Tropical 

 East Africa would have been very different from what it has been. 



It is not possible to speak too highly of the amount and quality of 

 the preliminary work on the habits and life-history of Tsetse-flies that 

 has already been accomplished by various observers, frequently 

 conducted at no little personal risk. 



It is evidently desirable that these investigators should have at their 

 disposal a full summary of our present knowledge concerning these 

 dangerous flies to aid them in their work. But, at present, the results 

 attained are widely scattered throughout various scientific and medical 

 journals of different countries, and are not readily available to workers 

 in the field. 



Such a resume was published in 1915, in French, by M. Emile Hegh, 

 of the Belgian Colonial Office ; and the Honorary Managing Committee 

 of the Imperial Bureau of Entomology recently decided to publish 

 an English edition of this pamphlet with such additional matter as 

 might be necessary to bring the information up to date. 



The work was placed in the capable hands of Major E. E. Austen, 

 D.S.O., of the British Museum (Natural History), who is well known 

 as one of the leading authorities on the flies of the genus Glossina, 

 and the present work, with its illuminating Introduction, is the outcome 

 of his labours. 



