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 MALARIA AND CROP PRODUCTION 439

The actaal available adult time in each family equals 1.21 man days. The actual number of available days for field work during the four months xmder consideration equals 76.5 days. A loss of time equivalent to the total loss of 13.79 families is equal to the loss of 1276.47 man days during these periods, when there was no surplus labor. There were 420.75 days lost tiiirough sickness and a loss of 855.72 days due to re- duced efficiency. Each day of neglect amounted to a total loss of $5.11, being a loss of $4.11 to the owner and $1.00 to the tenant. The con- clusion is that A loss equivalent to one day of man labor through malaria on this plantation, when the crops were in need of attention, and when there was no surplus labor, amounted to a net loss of $5.11 in the crop returns. Approximately $2,200 was lost through sickness and $4,300 through inefficiency from malaria.

The above survey was made in Madison Parish, Louisiana. The common house-frequenting Anopheles in this region is Anopheles quad- rimacuiatus Say. Anopheles punctipennis Say is common in nature while Anopheles crucians Wied., was encountered only in very Umited numbers. All three forms of the malaria parasite have been found to occur in this region, namely, tertian, estivo-autumnal and quartan, pre- vailing in the order named. The work was done in cooperation with the Maxwell- Yerger Co., Dr. Wm. P. Yerger, and Mr. Alexander Clark, Manager of Hecla plantation. Mound, La. The Anopheles determina- tions were made by Mr. P. Knab, of the U. S. National Museum. The blood examinations were made by Mr. J. K. Thibault, Jr., of this Bureau. Mr. Dates, of the Office of Parm Management of this depart- ment, furnished the data on the periods of the plantation operations, the available days per month for field work and the labor requirements of the crops.

BiBLIOORAPHT

1903. Herriek, Glenn W. The Belation of Malaria to Agriculture and Other Industries of the South. The Popular Science Monthly, April, 1903, pp. 521-525.

1909. Howard, L. O. Economic Loss to the People of the United States through Insects that Carry Disease. Bui. No. 78, Bureau of Ento- mology, U. S. Department Agr., 1909, pp. 40.

1913. Hunter, W. D. American Interest in Medical Entomology. Jh Ec Eni,, VI., No. 1, 1913, pp. 27-39.

1915. Van Dine, D. L. The Losses to Bural Industries through Mosquitoes that Convey Malaria. 80, Med, Jl,, March, 1915, pp. 184-194.

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