GENUS: CRITHIDIA 355 



cultures of L. ctenocephali. They state that a local infection occurred in 

 one guinea-pig inoculated in the testis. Noller {I9l2d) failed to infect 

 a dog with L. ctenocephali, and Chatton (1919) was equally unsuccessful 

 with mice. Shortt (1923a) attempted to infect dogs, monkeys, cats, mice, 

 pigeons, and frogs. The animals were examined by the smear and culture 

 method, but no evidence of infection was obtained. Yamasaki (1924) 

 also failed to infect mice and dogs, and noted that the flagellate differed 

 morphologically from Leishmania donovani. Drbohlav (1925) has failed 

 completely to produce any infection in a series of about 150 animals, 

 including one monkey, dogs, guinea-pigs, rats, and mice. In the light of 

 these failures the claims of Laveran and Franchini that practically every 

 animal inoculated acquired an infection are difficult to explain. 



Laveran and Franchini (1920a) also claim to have infected Euphorbia 

 plants {E. sauliana and E. pilosa) by inoculating them with cultures 

 of L. ctenocephali. The flagellates were said to be present in the plants 

 for at least thirty-five days. Shortt (1923) introduced cultures of this 

 flagellate into small pockets in E. royleana in India, where they survived 

 for six days. Some of the flagellates became elongated, and showed the 

 peculiar twisting of the posterior end of the body so characteristic of the 

 natural Euphorbia flagellate. 



By feeding bed bugs on cultures of the leptomonas of Pulex irritans 

 and cultivating from the intestine, Patton, La Frenais, and Rao (1921) have 

 shown that the flagellates can survive in the bug at least thirty-seven 

 days. Shortt (1923) has also shown that active multiplication of L. cteno- 

 cephali takes place in the stomach of bed bugs fed on cultures. Up to 

 forty-eight hours there may be a very heavy infection of the stomach, 

 after which it subsides, till in eight days very few flagellates occur. 

 Flagellates may, however, still be present in the hind-gut. Multiplica- 

 tion of the flagellate will also take place for a few days in bugs which have 

 died after feeding. The effect of giving the bugs feeds of blood after 

 ingestion of the culture has not been tried. 



Genus: Crithidia Leger, 1902. 



This genus was first created by Leger, L. (1902a), for a flagellate 

 {Crithidia fasciculata) which he had found in Anopheles maculipeyinis. 

 The name was based on the short, stumpy, leishmania forms which Leger 

 considered characteristic of this genus. As, however, these forms occur 

 in flagellates of the genera Leptomonas and Herpetomonas, this character 

 cannot be considered of generic value. Leger's genus Crithidia was 

 emended by Patton (1908a) in accordance with the definition given above. 

 The flagellates of this genus are purely parasites of invertebrates, and 

 in their most highly developed form are elongated organisms with a 



