The practical study of malaria : and other blood parasites / by J.W.W. Stephens and S.R. Christophers.

Date:
1904
Catalogue details

Licence: In copyright

Credit: The practical study of malaria : and other blood parasites / by J.W.W. Stephens and S.R. Christophers. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

    99/488 (page 79)
    Examination of Larvae Anopheline larvae cannot be mistaken for any other mosquito larvae (Fig. 21). 1. When undisturbed they lie hat along the. top of the water, and on every segment certain hairs (palmate hairs) actually indent the surface film. Observe that when viewed in certain lights from one side these identations can be plainly- seen. The appearance may even be as though the dorsum of the larvae projected from the water. This, however, is not the case. This appearance is diagnostic of the Anopheline larva. One species (M. turkhudi) does not, how- ever, rest in this position, but after rising to the surface in a horizontal position slowly sinks until the tail only touches the surface. Anopheline larvae, which are about to turn into nymphae, also sometimes tend to sink, so that the head is directed obliquely downwards (often seen in M. vossii). One species of Culex, at least (C. concolor), adopts a nearly horizontal attitude. The line of indentations of the surface film mentioned above is not, however, seen. 2. When disturbed, Anopheline larvae dart into the water, or what is very characteristic, if not greatly disturbed, they pass by a series of wriggling jerks along the surface of the water. When moving up towards the surface, an Anopheline moves in a much more irregular and jerky manner than a Culex larva. This is well demonstrated when living larvae in a cell are projected upon the screen of the lantern. The Culex larvae are seen rising by a series of regular