In this paper the author reports the results of three months' study of the saltwater-breeding member of the Anopheles gambiae complex of sibling species on Mauritius.There is evidence for the views that this form's distribution on the island is limited by the availability of suitable breeding areas, that it does not usually disperse far from the breeding grounds or coast, and that it is probably not an important vector except, perhaps, in the near vicinity of its breeding places.Some new evidence is presented in support of the view that this form (and forms A and B) are distinct species. This turns on the observed close coexistence of these three forms on Mauritius, supported by a theoretical consideration of what would be expected to happen in such circumstances if a system of random mating prevailed.Evidence is given that the Mauritian saltwater-breeding form of the A. gambiae complex is conspecific with the form occurring on the east coast of Africa.The practical importance of reaching general agreement on the evolutionary status of the members of the A. gambiae complex is emphasized.

(1964). Further Studies on the Chikungunya Outbreak in Southern Rhodesia in 1962. Annals of Tropical Medicine & Parasitology: Vol. 58, No. 1, pp. 45-51.

RECENT1–5 work has shown that at least four genetically distinct forms comprise the A. gambiae complex. Paterson6 has outlined arguments for regarding them as separate species. On the eastern half of Africa three species occur, ‘saltwater A. gambiae’ and the two freshwater-breeding species, species A and species B (= group A and group B3). These forms are apparently morphologically inseparable, though the frequency of females bearing four white bands on their palps, as against three, is usually much higher in populations of ‘saltwater A. gambiae’ than of the two freshwater-breeding species. Identification of the species is best achieved by performing crossing experiments with ‘type’ colonies of the different species. Interspecific crosses produce sterile F1 males1–4 with testes and accessory glands reduced to varying degrees according to the cross and its direction. In crosses between ‘saltwater A. gambiae’ and either species A or species B, F1 sex ratios supply further information1,2,4, but crosses between the two freshwater species usually produce normal sex ratios4. A physiological test (salinity-tolerance test) is available7 to distinguish first stage larvæ of ‘saltwater A. gambiae’ from those of either species A or species B.

(l) A descriptionption is given of the symptomatology and epidemiology of an outbreak of chikungunya which occurred from January to May, 1962, in the south-eastern area of Southern Rhodesia. (2) One strain of virus was isolated from a patient. This virus was identified by the complement-fixation, haemagglutination i?½ inhibition and neutralisation tests as chikungunya virus. (3) Antibody studies with the haemagglutination- inhibition test on acute and convalescent phase sera from patients showed a high prevalence of antibodies against chikungunya virus. (4) A total of 185 mosquitoes from 21 species were collected in the affected area in May towards the end of the outbreak. No virus was isolated from the mosquitoes. (5) The possible vectors concerned in the outbreak are discussed.

"Isolation of Germiston Virus, a Hitherto Unknown Agent, from Culicine Mosquitoes, and a Report of Infection in Two Laboratory Workers" published on Jan 1960 by The American Society of Tropical Medicine and Hygiene.

"Isolation of Bunyamwera Virus from a Naturally Infected Human Being and Further Isolations from Aedes (Banksinella) Circumluteolus Theo." published on Nov 1958 by The American Society of Tropical Medicine and Hygiene.