1 9 1 o] California Rodent Fleas 6 



J 



It seemed desirable to learn the jumping abilities of the com- 

 mon California species. An attempt was made to determine the 

 distance upon a horizontal plane, as well as the height that the 

 insect could jump. In the broad jump a few experiments were 

 conducted with P. irritans, the most active of our California 

 fleas. In this species we have found the jumping distance varies 

 considerably with the nature of the container from which the 

 insect is observed, e. g., a foothold of wood enables the flea to 

 jump a greater distance than one of glass. Since the irritans is 

 found to predominate on floors of houses, a surface of wood was 

 selected as the footing in our tests. In one experiment, five 

 specimens were permitted to jump at will and the jumps of each 

 were recorded. The mean average of ten jumps of each speci- 

 men gave a distance of 7 3-10 inches. The longest jump recorded 

 was II inches; this was made by a female. In another experi- 

 ment, a female, which was starved for five days prior to the test, 

 made four jumps of respectively 10 5-10, 11, 12, and 13 inches; 

 averaging 1 1 5-8 inches. Thirteen inches was the longest jump 

 recorded on a horizontal plane. A jump of 15 7-8 inches was 

 made downward at an angle of thirty degrees. 



This specimen was then permitted to feed fifteen minutes on 

 the arm of an attendant, after which it was carefully returned to 

 the container, and its jumps for five minutes recorded. The 

 longest jump after feeding was 12 inches. 



The jumping powers of squirrel and rat fleas were tested in 

 this manner: Three hundred and seventy-five live squirrel fleas 

 (C. acMtiis) and one hundred and fifty live rat fleas {C. fasciatus 

 and L. cheopis) were placed in two distinct lots in fifteen open 

 specimen vials in a water bath and left undisturbed for two days. 

 At the end of the period, the vials were examined, the water 

 bath and the surroundings being carefully inspected. No fleas 

 could be detected in the water bath or in the vicinity; the fleas 

 in the vials were counted, the original number being present. 

 They were apparently as active as when removed from their hosts. 

 The containers were cylindrical vials 3 3-8 inches in height and 

 I 3-16 inches in diameter. The same test was tried in open shell 

 vials of the next size smaller (3 1-8x1 inch) and the fleas were 

 found jumping into the water bath. 



L. cheopis, the rat flea, was tried for its jumping power. It 

 had been previously observed that members of this species were 

 unable to leap out of open shell vials 3 3-8 inches in height. It 



