Observations on the Emergence of Anopheles Mosquitoes

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  • Bureau of Entomology, United States Department of Agriculture


During the mosquito breeding seasons of 1921, 1922, and 1924 a total of 904.9 square yards of water surface in selected Anopheles breeding areas was covered by nets and 585 adult Anopheles, emerged therein, making an average daily emergence of 0.653 per square yard. The nets were located in areas which showed a higher larval rate, as determined by larval counts, than is generally found in the Anopheles breeding areas of the region.

An increase in the number of larvae present in the selected areas did not cause a proportionate increase in the rate of emergence. This may have been caused by a scarcity of suitable food in the concentrated areas, or by the activities of certain enemies of the larvae.

The females of Anopheles were found to emerge in somewhat greater numbers than the males. A discussion is given showing that this condition is usually met with among Anopheles although approximately equal numbers of the sexes have been observed at certain times, and at others, a large preponderance of males has been recorded.