ENTOMOLOGY

358 SANITARY ENTOMOLOGYof the flea and are voided in its feces and obtain entrance to the host bythe scratching in of feces of infected fleas, or by the licking up of thefeces or the flea.The five trypanosomes' are all taken up from the blood and passthrough a definite life cycle in the flea, passing out of its feces, andobtain entrance to the host by being licked up in the feces. This mayalso happen in the case of leptomonads. 0The crithidias and -leptomonads belong primarily to the fleas alone,and pass through their cycle of existence jn the flea body and out of itsfeces and are taken up by feeding on the infected feces, probably bythe larva. .The tapeworms are taken up as eggs by the larvre feeding in filthydirt. They develop in the flea and are taken into the vertebrate hostwhen it licks up the flea from its body.The filaria is taken from the blood of the host as an embryo, anddevelops in the :Bea, but we do not know how it gets back to thehost.In addition to all these diseases caused by organisms, fleas may causea dermatitis. This is especially true of the chigoe, Dermatophilu8 penetram,which becomes fixed to its host and sometimes even causes AIN­HUM, or the loss of a member, such as a toe. It will be discussed in thenext lecture on :Beas.REFERENCESBacot, A. W., and Martin, C. J., 1914.-Journ. of Hygiene, Plague SupplementIII, Jan. 14,1914, pp. ~3-439.Brumpt, E., 1913.-Bull. Soc. Path. Exot., vol. 6, pp. 169-1'10.Fantham, H. B., Stephens, J. W. W., and Theobald, F. V., 1916.-TheAnimal Parasites of Man.Herms, W. B., 1915.-Medical and Veterinary Entomology. MacmillanCo., 393 pp.Johnston, J. R., 1915.-Proc. Roy. Soc. Queensland, vol. !4, pp. 6S-91.Joyeux, Charles, 1916.-Bull. Soc. Path. Exot., vol .. 9, No.8, pp. 5'78-579.Laveran, A., and Franchini, G., 1913.-C. R. Acad. Sci., Paris, vol. 47,No. 18, pp. 744-747.Laveran, A., and Franchini, G., 1914.-Bull. Soc. Path. Exot., vol. 7.pp.605-6I1l.Liston, W. G., 1905.-Journ. Bombay Nat. Rist. Soc., vol. 16, pp.Jl5S-273.McCoy, G. W., and Chapin, C. W., 191!.-Journ. Infect. Diseases, vol.10, No.1, pp. 61-72.