A monograph of the Anopheles mosquitoes of India / by S.P. James and W. Glen Liston.

  • James, Sydney Price, 1890-
Date:
1911
Catalogue details

Licence: In copyright

Credit: A monograph of the Anopheles mosquitoes of India / by S.P. James and W. Glen Liston. Source: Wellcome Collection.

Provider: This material has been provided by London School of Hygiene & Tropical Medicine Library & Archives Service. The original may be consulted at London School of Hygiene & Tropical Medicine Library & Archives Service.

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    A MONOGRAPH OF THE ANOPHELINE MOSQUITOES OF INDIA. CHAPTER I. A GENEEAL ACCOUNT OF MOSQUITOES. OSQUITOES or gnats (CULICIDtE) belong to the order of insects known as DIPTERA. As is well-known, a typical member of the class INSECTA has four wings, but it is characteristic of members of the order DIPTERA that the hinder pair of wings are so reduced in size as to form only small knobs called balancers or halteres, so that DIPTERA are often spoken of as two-winged flies/' Other important characters of members of this order are that the mouth parts are adapted for sucking—sometimes also for piercing—and that the insects undergo complete metamorphosis—a term which is explained by Claus in the following manner :— The more complete the agreement between the just-born young and the adult sexual animal so much th? greater will be the duration of the embryonic development and the more complicated the developmental piocesses of the embryo. The post-embryonic development will, in this case, be confined to simple processes of growth. When, however, the embryo is born in an immature condition and at a relatively low state of organization, the post-embryonic development will be more complicated, and the young animal, in addition to its increase in size, will present various processes of transformation and change of form. In such cases the just-hatched young, as opposed to the adult animal, is called a Larva and develops gradually to the form cf the adult sexual animal. The development of larvae, however, is by no means direct and uniform, but is complicated by the necessity for special contrivances to enable them to procure food and to protect themselves ; sometimes taking place in an entirely different medium, under different conditions of life. This kind of post-embryonic development is known as metamorphosis. The phenomena of metamorphosis are well shown in the life history of insects. The different stages through which mosquitoes pass before they reach the adult state may, for example, be briefly described in the following way :— The adult female mosquito lays its eggs on the surface of water. The eggs float on the water for some days (two to four), after which time they hatch into small wriggling animals called larvw. A]