Illustrations of African blood-sucking flies other than mosquitoes and tsetse-flies / by Ernest Edward Austen.

  • Ernest Edward Austen
Date:
1909
Catalogue details

Licence: Public Domain Mark

Credit: Illustrations of African blood-sucking flies other than mosquitoes and tsetse-flies / by Ernest Edward Austen. Source: Wellcome Collection.

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    dorsal ridge, which may exhibit a depression in the median line partially dividing it into two, a rounded tubercle on each side, and four similar ventral ones. The last segment bears a terminal conical retractile prolongation, containing the stigmata or respiratory apertures in a vertical slit, while on the ventral side the anus is situate between a pair of prominent tumid lips. Tabanid larvae live in water, wet sand or mud, earth or decaying vegetable matter ; they are carnivorous, and prey upon snails, beetle-larvae, small Crustaceans, worms, etc. The pupa, which is not unlike that of a Lepidopterous insect, and in colour dull yellowish or some shade of brown, remains stationary, and is usually found in earth or damp rubbish at the edge of water. The thorax bears a pair of somewhat ear-shaped spiracular prominences ; each abdominal segment is encircled with a ring of slender spines on its distal third, and there are six sharp spines or teeth at the tip of the terminal segment. So far as present knowledge goes, there is no Tabanidae and reason to regard Tabanidse as regular carriers of Disease. any form of disease among human beings, although it is obvious that these flies, like any other blood¬ sucking Diptera, may occasionally convey pathogenic organisms, such as Trypanosoma gambiense or Bacillus anthracis* With respect to domestic animals, however, the matter would seem to rest on a somewhat different footing, for Tabanidse as a whole may be considered as pests of animals more than of human beings, and the relatively considerable amount of blood that many of these flies are able to imbibe, owing to their large size, obviously increases the risk of their sucking up micro-organisms from infected animals. It will be seen from the statements under the heading “ Tabanus and * Dr. Arthur Pearson, P.M.O., Union Miniere du Haut-Katanga, writing from Ruwe, Katanga District, Congo Free State, August 3rd, 1908 (Brit. Med. Journal, October 17th, 1908, p. 1218) on “Sleeping Sickness,” says:—“With regard to the possibility that other biting flies, such as Tabanidce, may infect, to my mind one may point to the fact that, whereas these are apparently distributed all over the country, and for three months of the year are so plentiful as to be productive of very considerable discomfort even to a clothed European, the disease has confined itself strictly to the riparian population on those rivers where [Glossina] palpalis is found. Surely this evidence is very powerful ... I do not deny, of course, the possibility of infection when one of the Tabanidce, interrupted in its feed on an infected native, plunges its still wet proboscis into an uninfected man. But such cases must be very rare, judging from results.”