Mosquitos and malaria : a study of our knowledge on the subject at the beginning of the year 1900 with an account of the natural history of some mosquitos / by Cuthbert Christy.

  • Cuthbert Christy
Date:
1900
Catalogue details

Licence: Public Domain Mark

Credit: Mosquitos and malaria : a study of our knowledge on the subject at the beginning of the year 1900 with an account of the natural history of some mosquitos / by Cuthbert Christy. Source: Wellcome Collection.

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    In the female they are plain, with the exception of some fine hairs at the base of each joint (PL I., fig. 3). It is said that only the female Culex sings. This is a point upon which further study is needed. It is possible that all species are not alike in this respect. We have satisfied ourselves that both the male and female of at least one species of Culex does so. It is asserted that both sexes of Anopheles are silent, and that the bite of the female is less painful than that of Culex, people frequently not being aware of their presence, or of having- been bitten by them. The male and female of all mosquitos each possess a pro¬ boscis. but only the females bite and suck blood. In some species, for example, Corethra, the proboscis is so short that it is almost invisible to the naked eye. These gnats, we think, do not suck blood. Mosquitos are fecundated on the wing shortly after feeding. On the second day after feeding the ovaries appear as two thick yellow masses loosely attached to the alimentary apparatus and to the terminal segments of the body (PI. II., fig. 5). On the third day the eggs are usually laid and the insect frequently dies if it has not been fed again on the previous night. Mosquitos are believed to return to the spot in which they were born to lay their eggs. Hence the places probably remain permanent breeding haunts. According to Grass], Anopheles bites only at sunset and sun¬ rise. Ross says (B. M. J,, Sept. 30, 1900, p. 809), they bite at night, sleeping on the walls during the day-time, where they can be easily caught by placing a test tube or a bottle slowly over them. The tube is then stoppered with cotton-wool. In forty-eight hours after feeding, the stomach becomes empty, then the eggs are laid and the insect is ready to feed again. This can be effected by placing the mouth of the tube on the skim Presently Anopheles “ lays hold ” and ouro-ss itself even in the day-time. It even voids blood while suck-