. Sanitary entomology; the entomology of disease, hygiene and sanitation. ge spherical bodies contains at first a number of nu-clei, kinetonuclei, and developing flagella, the original flagcllum still re-maining attached for a time. The cytoplasm then divides into daughter^This synonymy is according to Mesnil. Bull. Inst. Past. vol. 17, p. 190. DISEASES CARRIED BY FLEAS 353 trypanosomes which are contained within an envelope, formed by the peri-blast of the parent parasite. Inside the periblast envelopes are a numberof daughter trypanosomes wriggling very actively; the envelope finallybursts a
. Sanitary entomology; the entomology of disease, hygiene and sanitation. ge spherical bodies contains at first a number of nu-clei, kinetonuclei, and developing flagella, the original flagcllum still re-maining attached for a time. The cytoplasm then divides into daughter^This synonymy is according to Mesnil. Bull. Inst. Past. vol. 17, p. 190. DISEASES CARRIED BY FLEAS 353 trypanosomes which are contained within an envelope, formed by the peri-blast of the parent parasite. Inside the periblast envelopes are a numberof daughter trypanosomes wriggling very actively; the envelope finallybursts and releases them, usually about eight, in the host cell. Thedaughter forms escaping from the host cell into the stomach of the fleaare fully formed, long trypanosomes. They then pass into the rectum,where they assume a crithidial phase, and become pear-shaped. Thekinetonucleus has traveled anteriorly past the nucleus toward the flagel-lum. The crithidial forms attach themselves to the wall of the rectumand multiply by binary fission. In this forai the parasite probably. SPOROGONY Host I Mice,Rats (,^fus,lVlYoxus, Meriones). HoSrU Fleas , Xenopsylla). LIFE CYCLE OF TRYPANOSOMA LEWISI. I111. a J. (Pierce.) exists throughout the life of the insect. From the crithidial forms smallinfective trypanosomes develop. These are small, broad, and stumpy,with the kinetonucleus behind the nucleus, and the flagellum (1913) declares that transmission occurs exclusively by rodentslicking up the feces of infected fleas. These feces contain little meta-cyclic trypanosomes which are able to traverse healthy mucous mem-branes. The life cycle as described has been figured graphically in the samescheme as used in previous lectures. Trypanozoon nahiasi (Railliet), a rabbit trypanosome, presumablynonpathogenic, attacks the genus Lepus and was found by Brumpt(1913) to be transmitted by the rabbit fleas Ctenocephalus leporis(lic
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