viii INTEODUCTION. 



to be proved ; but the importance of the occurrence of Gl. 

 morsitans (in addition to other specifes of Tsetse) in Togo is 

 obvious in connection with the fact that Tsetse-fly disease (called 

 Surra by German writers) has also been shown to exist there. 



Before closing my list of acknowledgments, a word of special 

 thanks is due to my artist, Mr. A. J. Engel Terzi, for the 

 unremitting care and attention bestowed by him upon the 

 coloured plates. Mr. Terzi's beautiful drawings have been well 

 reproduced by Messrs. Carl Hentschel & Co., with the result 

 that the reader now has the advantage of possessing accurate 

 representations of Tsetse-flies, such as have not hitherto been 

 available. I have also to thank Mr. Terzi for the trouble that 

 he has taken over the drawings for the figures that illustrate 

 the text. To Dr. L. W. Sambon I am indebted for references 

 to certain papers dealing with Tsetse -fly disease, as well as for 

 kind assistance in other ways ; while I have to thank my uncle, 

 Dr. T. P. Smith, for the preparation of the Index to this 

 volume. Last, but by no means least, I have to express my 

 gratitude to Dr. H. J. Hansen, of Copenhagen, who furnished 

 within a very brief period the valuable account of the mouth- 

 parts in Glossina and Stomoxys contained in Chapter V., in 

 addition to preparing the admirable drawings reproduced on 

 Plates VIII. and IX. I can but consider myself fortunate in 

 having secured the co-operation of so painstaking and accom- 

 plished an investigator, who had previously paid special attention 

 to the mouth-pai'ts of Diptera, and is already well-known owing 

 to his work on the subject. 



In the first portion of the "Bibliography" (Chapter VI.) it 

 was deemed advisable in most cases to quote the actual passages 

 in extenso in addition to giving references, since the majority 

 of the volumes referred to are out of print or otherwise inacces- 

 sible to ordinary students, not to speak of those who may use 

 this book in outlying portions of the Empire. The " Biblio- 

 graphy " cannot, unfortunately, lay claim to anything like 

 completeness. It was thought necessary that this volume should 

 be published with as Uttle delay as passible, and to have con- 

 sulted all the books on Africa south of the Sahara, not to speak 

 of the Proceedings of Foreign Geographical Societies, in which 

 no doubt many valuable notes lie buried, would have entailed 

 many months' more work. Such as it is, however, it is to be 

 hoped that a perusal of the * ' Bibliography " will give the reader 

 a fairly good idea of the bionomics and distribution of Tsetse- 



