ENTOMOLOGY

THE LIFE HISTORY AND CONTROL OF FLEAS 36358 days, the Indian rat flea 38 days, and the bird or chicken flea (Ceratoplzillusgallinae) 1fl7 days. When fed daily this longevity was greatlyincreased; human flea 518 days, European rat flea 106 days, dog fleafl84 days, Indian rat flea 100 days, and the bird flea 845 days. Mitzmainfound the European rat flea to live 160 days in California and the groundsquirrel flea (Ceratophyllua acutua) 64 days. In warm weather thelong.evity without food is but a fe,v days.The human flea (Pulex irritana) (figs. 66,67) was formerly thoughtto restrict its attention largely to man. Investigators have found, however,that it probably develops normally on the hedgehog and othersstate that it is occasionally found on dogs and cats, especially during thewinter. Our own observations indicate that it is a very common parasiteof hogs; so much so in fact that it might be called the hog flea insteadFIG. G7.-The human fiea, Puler» irritana: Adult male. Greatly enlarged.From U. S. D. A. Bull. 248, figs. 5, G.(Bishopp.)of the human flea. Also that it may be found in considerable numberson dogs at all times of the year even in regions where it is not a pestof importance to man. It has been ta.ken on several species of rats, butin limited numbers. This form appears to be well adapted to a freeexistence, usually leaving the host after partaking of a blood meal andthis habit may tend to make it of greater importance as a disseminatorof disease. It has almost world-wide distribution but its abundance indifferent regions varies greatly. In the United States it is very prevalentin California and the Southwestern States where it is the principalcause of flea annoyance t() man.The dog and cat fleas (Ctenocephalus cania Curtis and Ct. feliaBouche (fig. 65) may be discussed together as their habits appear to bevery similar and as some authors stilI" believe they are not distinct speciesbut only varieties. They have a rather wide range of hosts, including thedog, cat, man, and a number of wild animals, especially of the dog and