igio] California Rodent Fleas 75 



moment the egg was laid by its parent. An hour after the egg 

 was laid it ^^'as placed in a small vial with a little sawdust, sand, 

 wheat grains and squirrel hair. It was allowed to develop in this 

 environment until matured. 



Stage of development Date Age of flea 



Egg laid May 4th, 1909 



Hatched May 12th, 1909 8 davs 



Moulted (second stage) .Mav 18th, 1909 14 davs 



Moulted (third stage) May 2Sth, 1909 24 davs 



Cocoon June 9th, 1909 36 days 



Adult July 10, 1909 67 days 



Alive (never having been fed) Aug. 11, 1900 99 days 



The English workers in India ascertain the length of time 

 which adult fleas live on rats as 41 days. The longest life of this 

 species on an exclusive diet of human blood was observed to be 

 27 days. We ha\'e managed to keep this species (cheopis) alive 

 for a period of 36 days by feeding on man. The length of life 

 without feeding was also noted. This period varied in the experi- 

 ments of the English Commission according to the environments 

 in which the fleas were maintained. In the absence of liquid food 

 supply, fleas could live in bran for six days, in gunny sacking a 

 similar time, and in sand with moist cowdung for 13 days. From 

 onr observations we have found the majority of fleas of all species 

 to die in five days unless a moist medium was provided. 



As we have stated above rat and squirrel fleas may be kept 

 alive for a considerable time when moisture is provided in some 

 form. It is interesting to note that fleas which have never 

 tasted animal food, having emerged from the cocoon and kept 

 under the same conditions in similar material as fleas taken direct- 

 ly from the host, will prove longer lived. A num^ber of specimens 

 of Ceratophyllus acutits removed from a ground squirrel and kept 

 in moistened wheat grains and sawdust lived for 26 days. An 

 equal number of fleas of the same species bred from cocoons in the 

 laboratory were kept without a host in a similar medium. One 

 male lived 38 days and a female lived for 65 days. 



In a series of experiments in which fleas taken from healthy 

 rats and squirrels were fed daily on the arm of a man we 

 attempted to determine the maximum longevity of these para- 

 sites. The fleas were placed individually in open test tubes and 

 at feeding time the tubes were inverted over the arm of one of 

 the laboratory attendants. Fleas were thus applied daily for a 

 period of from 5 to 15 minutes, but only the actual feeding time 

 was recorded. The average was about five minutes. 



