BENGAL PUBLIC HEALTH DEPARTMENT.
Preliminary Report of a Malaria Survey of Calcutta and Environs by M. O. Tirunarayana Iyengar, B. A., Entomologist to the Department of Malaria Research, Bengal.
The author has conducted a mosquito survey of Calcutta and its environs during the past two years and this paper deals with the results, more especially from the point of view of sanitation and disease-prevention. No thorough survey of the culicid fauna of Calcutta has up to now been made. Previous work in this direction has either been too local or admittedly incomplete. Stephens and Christophers made some observations in regard to Calcutta anopheles during the year 1900. Since then, Sir Leonard Rogers and Dr. U. N. Brahmachari have also made certain observations of the ano-phelines of the city. Dr. Brahmachari made periodic observations of the anophelines breeding in the Campbell Hospital tank. During 1912-13 Major McGilchrist conducted a Stegomyia survey of the Port of Calcutta, but this is far from complete as it was conducted for a few months only, and that at a period, viz., December and January, when the Stegomyias had practically stopped breeding. The surveys of Paiva and Nandi, chiefly in regard to Stegomyia, were concerned only with certain parts of Calcutta. In 1914, Major Christophers pointed out the necessity for a complete scientific survey, and suggested that such a survey should be undertaken extending over five years. This proposal, though endorsed by the conference convened for the purpose of framing a "scheme for securing better sanitary control over the Port of Calcutta and environs," has not yet been carried out. This paper is the result of the author's attempt to make a survey of Calcutta from the point of view of mosquito-borne diseases.
Kidderpore.-Various parts of Calcutta have been surveyed. The first work undertaken was in the area of the new docks at Bracebridge Hall near Kidderpore. This area was surveyed in great detail during 1917-18, every species of mosquito found here being identified. The area, which is 4 miles by 3, contains innumerable collections of water. Few of the numerous ponds and pools which afforded plentiful facilities for the collecting entomologist, were found free from mosquito larv.
Six species of anophelines are very common in the area, viz., A nopheles rossi (Giles), A. barbirostris (Van der Wulp), sinensis (Wied), jamesi (Theob), fuliginosus (Giles) and listoni (Liston). The variety of A. listoni is not the type species but the variety described by Theobald as var. alboapicalis. This variety is more common in Bengal than the type species, and in some places, as in the Dooars, both kinds occur. A single specimen of A. jeyporensis (and one of what I believe to be a variety of A. gigas) were also collected. A winter variety of A. jamesi, comparable to the adeyi variety of A. fuliginosus, was also found, but, as the type specimens were all destroyed by mites when I was away from duty, the publication of this description has been withheld. As regards the non-anophelines occurring in Kidderpore we have about eleven species, including Desvoidea obturbans (Walker), Stegomyia fasciata (Fabr), Radioculex clavipalpus (Theob), Leucomyia gelida (Theob), Culex impellens (Walker), C. fatigans (Wied), C. concolor (Desvoidy), Mansonioides annulifera (Theob), A edeomyia squam-mipenna (Arri), Mimomyia minuta (Theob) and a species not yet identified. The Stegomyias occur wherever coolie lines exist. The various other species occur in less inhabited portions of the area under survey.
Other suburbs of Calcutta.-Other parts of Calcutta have not yet been surveyed in such detail as Kidderpore, and the work so far done relates especially to the anophelines present. Much attention has not yet been paid to culicines other than Stegomyia. Stegomyia is plentiful in some localities and is found to occur more frequently in thickly populated parts like Entally