46 



JOURNAL OF ECONOMIC ENTOMOLOGY 



[Vol. 8 



In reckoning the total cost of mosquito control, the lump sum ex- 

 pended should not be considered because the most tangible and imme- 

 diate benefit derived does not admit of similar aggregation. Stating 

 the matter in another way, it should be said that inasmuch as the most 

 tangible and immediate benefit is personal, the cost should be reckoned 

 on a per capita basis. From this standpoint mosquito control in 

 County A cost 5.07 cents and 5.42 cents in 1913 and 1914; in County 

 B, 6.37 cents, 11.9 cents and 11.37 cents in 1912, 1913 and 1914; 

 while in County C it cost 10.57 cents, 28.22 cents, and 15.89 cents in 

 1912, 1913 and 1914. 



For an explanation of these differences in per capita cost of the work,, 

 the conditions under which it was done must be examined. The work 

 of 1912 began late and represents only 5-6 months. During the only 

 years (1913 and 1914) when the three counties (A, B and C) were at 

 work coincidently the percentage of the total expenditure, in Counties 

 A and B, devoted to the salt marsh, was the same while County C spent 

 about one-half as much as each of the others. The upland area of 

 County A is only one-third that of County B and less than one-half 

 that of County C. County A has a population of 13,275 to the square 

 mile. County B, 4,515 and County C, 1,526. 



On the basis of unit area (say per square mile) County A expended 

 $461 in 1913 and $512 in 1914 as compared with $375 and $357 in 

 County B, and $272 and $195 in County C. This higher unit-area 

 cost is not due to poorer drainage conditions, for the upland in County 

 A is better drained than that of either County B or County C. It 

 seems rather to be chargeable to the larger number of breeding places 

 which is incident to a denser population. 



On the basis of per capita cost per unit of upland area the results are 

 quite different. The per capita cost per square mile was 3.4 cents in 

 1913 and 3.8 cents in 1914 in County A, 8.3 cents and 7.8 cents in 

 County B and 17.8 cents and 12.8 cents in County C. 



It is distinctly indicated by these facts that other things being 

 approximately equal, the cost of controlling mosquito breeding on the 

 upland increases per unit of area as the population grows denser, but 

 that the per capita cost decreases as the density of population increases. 



Results of Mosquito Conteol 



The results of mosquito control appear in increased comfort and 

 health, and in increases in property values. No investigation of effect 

 on property values has been made and there exist no reliable malarial 

 records on which to base conclusions. 



Evidences of results must therefore appear in what the people who 

 are protected say and do about it. The first evidence is the attitude 



