1915] Lyon — Noies on the Cat Flea 125 



Soon after the animals had been killed, their fur was carefully 

 gone over with a fine-toothed comb and the fleas present on each 

 were counted. As the time was limited, five cats were chosen as 

 a unit. These were selected at random and the lot contained both 

 homeless and strayed pet cats. The extent of infestation varied 

 greatly, but contrary to expectations seemed to be as great in the 

 pets as in the homeless ones. No doubt, more fleas could have 

 been obtained from individual cats if it had been possible to ex- 

 amine each animal exhaustively, but as all were gone over with 

 the same thoroughness, the conclusions as to the comparative 

 abundance can be regarded as trustworthy. 



The data obtained have been summarized in the following table: 



Number of animals examined 139 



Number of animals with fleas 114 



Number of animals without fleas 25 



Total number of fleas 590 



Greatest number per cat 30 



Smallest number per cat 1 



Average number per cat 4 . 24 



Monthly Average per Cat. 



December 3 . 75 



January 3 . 85 



February 2.3 



March 1 .08 



April 2 . 52 



May 3.1 



June 3 . 98 



July 10.05 



A number of very interesting facts are brought out in the table, 

 and some are rather different from what had been anticipated. It 

 is, of course, common experience that fleas are less abundant in 

 the winter than in the summer, but so great a variation had not 

 been expected, since the adult insects would not seem to be greatly 

 affected by temperature, living as external parasites of a warm 

 blooded animal. The larvae are, of course, subjected to a much 

 greater range of temperature, as they live in the nest of the animals 

 which they infest or in accumulations of dust and animal refuse 

 nearby. This probably accounts for the late appearance of 

 considerable numbers of fleas in the spring, while their persistence 

 well into the winter may be due to the continued warm environ- 



