County. Of these, 1,882 individuals were females and 
1,060 were males. This distribution of the sexes gives 
a ratio of 100 females to 56.3 males, or about 2 females 
to 1 male. Month by month, the ratio remained about the 
same. The number of males and females carried on any 
one rabbit varied from many females per male to more 
males than females. However, when the total popula- 
tion of fleas present on rabbits each season was con- 
sidered, the same 2-to-] ratio was observed, even in 
the springtime when the fleas were suspected to be most 
actively breeding. Shaftesbury (1934) found a similar 
ratio of sexes, 100 females to 56.1] males, for this flea 
in North Carolina. His figures are based on a small 
number of specimens, 189, 
The highest number of common eastern rabbit fleas 
found on one rabbit was 101, collected March 25, 1953. 
This case was considered unusual; a few other rabbits 
harbored 70, 80, or even 90 fleas each, but most were 
less heavily infested. The average number of these 
fleas per rabbit examined was approximately 4. Some 
rabbits were found to have no fleas at all, but apparent- 
ly such a condition is temporary. 
Table 3._Number of specimens of the common eastern rabbit flea, Cediopsylla simplex, taken from cottontails examined 
in Lee County, Illinois, and average number per rabbit infested; also, number and per cent of rabbits infested. 
Rabbits Fleas 
Number | Number | Mean Per Cent Total Average Number Per 
Month Year Examined Infested Infested Number Rabbit Infested, 
With Fleas | WithFleas Taken 1952—1954 
1952—1954 
January 1952 - = = 
1953 9 8 90 43 5 
1954 1 1 8 
February 1952 - _ = 
1953 113 65 70 439 7.4 
1954 40 39 330 
March 1952 - - - 
1953 ll ll 100 366 33.3 
1954 — _ - 
April 1952 ~ - = 
1953 5 5) 100 123 24.6 
1954 — = = 
May 1952 4 4 13 
1953 12 8 75 205 18.2 
1954 — - = 
June 1952 52 27 104 
1953 9 4 54 24 6.0 
1954 6 5 86 
July 1952 13 5 15 
1953 63 24 40 100 4.0 
1954 4 3 15 
August 1952 15 11 24 
1953 8 1 57 1 2.0 
1954 5 8 
September 1952 77 40 150 
1953 - - 5? _ 3.7 
1954 _ - — 
October 1952 74 37 181 
1953 ie 39 56 142 4.6 
1954 19 7 102 
November 1952 7 31 105 
1953 38 36 90 202 4.9 
1954 26 25 147 
December 1952 _ — a 
1953 2 2 100 9 4.5 
1954 = = = 
TOTAL P 715 ax yee | 2,942 
12 
