Abstract

Chief among the blood-sucking insects are mosquitoes, sand- flies, bed-bugs and head-lice. A knowledge of the life history of these insects would be of great help in dealing successfully with their extermination or diminu- tion. Mosquitoes, as is well known, breed in stagnant water. The females lay a number of floating eggs raft-fashion closely-packed on the surface of stagnant water, the requisite condition being the presence of sufficient algæ as food for the offspring. From the eggs hatch out "wrigglers" which after undergoing the final moult turn into pupæ. The pupal stage lasts but for about 48 hours, when the mature insect emerges. The whole life-cycle from egg to mos- quito is completed in about to days. The popular belief is that mosquitoes breed only in ill-drained marshes and swampy jungles and ponds or any other large reservoir of water, but occurrence of mosquito larvae has been commonly noted not only in large stagnat- ing sheets of water, but also in gutters, in and outside houses, under culverts, in broken pots and vessels, in leaf sheaths, and even in tin trays used for the stands of cots or meat-safes, and in short, wher- ever there is sufficient water and the requisite conditions.

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