2 Deevey, E. S. 1960. ‘The Human Population’, Scientific American, CCIII (3), 194–204.
3 Cockerell, T. D. A. 1907. ‘A Fossil Tsetse Fly in Colorado’, Nature, Lond., LXXVI, 414; 1909. ‘Another Fossil Tsetse Fly, Nature, Lond., Lxxx, 128; 1919. ‘New Species of North American Fossil Beetles, Cockroaches and Tsetse Flies’, Proc. U.S. Nat. Mus., LIV, 301–11.
4 Baker, J. R. 1963. ‘Speculations on the Evolution of the Family Trypanosomatidae Doflein, 1901’, Exper. Parasitol., XIII, 219–33.
5 Another possibility, considering an even older phylogenetic origin, would be that of flagellates circulating in plant-sap, then adapting themselves to insects feeding on these plants, and later developing in vertebrates when some of the insect groups began feeding on blood. Certain plants, like some Euphorbia species, do harbour phytoflagellates and lend some support to this possibility.
6 Clark, J. D. 1959. The Prehistory of Southern Africa. Penguin Books, Harmondsworth, Middlesex; 1960. ‘Human Ecology during Pleistocene and later Times in Africa South of the Sahara’, Current Anthropology, I, 307–24;Washburn, St. L. 1961. Social Life of Early Man. Viking Fund Publ. in Anthropology, no. 31.
7 Van Den, Berghe L. and Lambrecht, F. L. 1963. ‘The Epidemiology and Control of Human Trypanosomiasis in Glossina morsitans Fly-Belts’, Amer. J. Trop. Med. & Hyg., XII, 129–64.
8 Clark, 1959 and 1960;Washburn, 1961.
9 Clark, 1959;Washburn, 1961.
11 Ashcroft, M. T. 1959. ‘A critical Review of the Epidemiology of Human Trypanosomiasis in Africa’, Trop. Dis. Bull., LVI, 1073–93; 1963. ‘Some Biological Aspects of the Epidemiology of Sleeping Sickness’, J. Trop. Med. & Hyg., LXVI, 133–6;Hoare, C. A. 1950. Handbook of Medical Protozoology. The Williams & Wilkins Company, Baltimore; 1957. ‘The Classification of Trypanosomes of Veterinary and Medical Importance’, Veterinary Reviews and Annotations, III 1–13;Willett, K. C. 1956. ‘The Problem of Trypanosoma rhodesiense, its History and Distribution, and its relationship to T. gambiense and T. brucei’, East African Med. J., XXXIII, 473–9.
12 Willett, K. C. 1956. ‘An Experiment on Dosage in Human Trypanosomiasis’, Ann. Trop. Med. & Parasit., L, 75–80.
13 Van Hoof, L., Henrard, C. and Peel, E. 1937. ‘La Piqure de la Glossina infectieuse’, Ann. Soc. Belg. Med. Trop., XVII, 59–62.
14 There is strong evidence to believe that there is a marked difference in the anticoagulant properties of the salivary gland excretions between flies of the morsitans-group and those of the palpalis-group. In the latter, the very strong anticoagulant action enables these flies to feed on the nucleated blood of reptiles and birds without danger of blocking their mouthparts. The difference in the properties of the salivary gland fluid may partially be responsible for regulating the number, or forms, of the trypanosomes it harbours.
15 Lester, H. M. O. 1933. ‘The characteristics of some Nigerian Strains of the Polymorphic Trypanosomes’, Ann. Trop. Med. & Parasit., XXVII, 361–95.
16 WElls, L. H. 1963. Personal communication.
18 Summers, R. 1960. ‘Environment and Culture in Southern Rhodesia: A Study in the “Personality” of a Land-Locked Country’, Proc. Amer. Phil. Soc., CIV, 266–92.
19 Moreau, R. F. 1933. ‘Pleistocene Climatic Changes and the Distribution of Life in East Africa’, J. Ecol., XXI, 415–35.
20 Ford, J. and Leggate, B. N. 1961. ‘The Geographical and Climatic Distribution of Trypanosoma Infection Rates in G. morsitans-group of Tsetse Flies’, Trans. R. Soc. Trop. Med. & Hyg., LV, 383–97.
21 Ford, J. 1960. Distribution of African cattle. Proc. Ist Sci. Congress, Salisbury, S. Rhodesia, pp. 357–65.
24 Clark, J. D. 1962. ‘The Spread of Food Production in Sub-Saharan Africa’, J. Afr. Hist., III, 211–28.
26 Fuller, C. 1923. ‘Tsetse in the Transvaal and Surrounding Territories; an Historical Review’, Trop. Dis. Bull., XXI, 785.
27 Dicke, B. H. 1932. ‘The Tsetse Fly's Influence on South African History’, S. Afr. J. Scs., XXIX, 792–6.
28 Anderson, Ch. J. 1857. Lake Ngami: Four Years Wanderings in the Wilds of South Western Africa. (1850–1854.) Hurst & Blackett, London.
30 Ford, J. and Hall, R. de Z. 1947. ‘The History of the Karagwe, Bukoba District’, Tanganyika Notes and Record, XXIV, 3–27.
31 Van Den, Berghe L. and Lambrecht, F. L. 1956. ‘Étude biologique et écologique des Glossines dans la région du Mutara, Ruanda’, Acad. R. Sci. Col., mémoire T.IV, fasc. 2, pp. 1–101; 1962. ‘Étude biologique et écologique de Glossina morsitans West, dana la région du Bugesera, Rwanda’, Acad. R. Sci. d'Outre-Mer, mémoire T.XIII, fasc. 4, pp. 1–116.
33 Curtin, P. D. 1963. Personal communication.
34 Glover, P. E. 1961. The Tsetse Problem in Northern Nigeria. Printed for the Colonial Office by Patwa News Agency (E.A.) Ltd., Nairobi, Kenya.
35 Scott, H. H. 1939. A History of Tropical Medicine. The Williams & Wilkins Company Baltimore.
36 Cf. Levtzion, N. ‘The Kings of Mali’, J. Afr. Hist., IV, 3 (1963), 350.
37 Clark, J. D. 1963. Personal communication.
38 Bloss, J. F. E. 1960. ‘The History of Sleeping Sickness in the Sudan’, Proc. R. Soc. Med., LIII, 421–6.
39 Van den, Berghe L. and Lambrecht, F. L. 1963.
41 Van den, Berghe L. and Lambrecht, F. L. 1962.
44 Buxton, P. A. 1955. The Natural History of Tsetse Flies. Lond. School of Hyg. & Trop. Med., memoir no. 10. Lewis, H. K., London.
46 Glover, P. E., Le Roux, J. G. and Parker, D. F. 1958. ‘The Extermination of Glossina palpalis on the Kuja-Migori River Systems with the Use of Insecticides’, Intern. Svi. Comm. Trypanosomiasis Res. Comm. Techn. Coop. Afr., Brussels 1958, Publ. no. 41, 331–42.
47 Van den, Berghe L. and Lambrecht, F. L., 1963.
48 I should like to express my sincere appreciation to Dr J. D. Clark, Professor of Anthropology at the University of California (Berkeley), for his encouragement and advice; to Dr Philip D. Curtin, Professor of History at the University of Wisconsin, for his critical review and valuable suggestions; to Dr L. H. Wells, Professor at the University of Cape Town, South Africa, for his information on fossil antelopes and to Drs J. R. Audy, F. L. Dunn and D. Heyneman of the Hooper Foundation staff who have given time for reading and discussing the manuscript.