1. a Tsetse & Trypanosomiasis Control Branch , P.O. Box 8283, Causeway, Zimbabwe
2. b The Natural History Museum , P.O. Box 240, Bulawayo, Zimbabwe
3. c Institut fur Biogeographie, Zentrumfur Umweltforschung , Universitatdes Saarlandes , D-6600, Saarbrucken, Germany
4. d Dipartimento di Biologia Ambientale , Universita deglistudi di Siena , Via delle Cerchia, 3-53100, Siena, Italy