GENUS: LEPTOMONAS 



349 



form in the dog flea will become a synonym. The first-named form is one 

 which Mackinnon (1909) described in Ctenophthahnus agyrtes, and which 

 she named Herpetomonas ctenophthalmi. Swingle (1911) gave the name 

 H. pattoni to one which he found in species of Ceratophyllus and Pulex, 

 while Chatton and Delanoe (1912a) identified as this species a form in 

 the larv8B and adults of C. fasciatus. Brumpt (1913) gave the name 

 H. debreuli to a flagellate of C. sciurorum, and Laveran and Franchini 

 (1915) the name H. ctenopsyllce to one in Ctenopsylla musculi. Patton 

 and Rao (1921) gave the name H. pulicis to the form in the human flea, 

 P. irritans, but it is a synonym of Crithidia pulicis. This form, again, 

 was first seen by Basile (191 1«), who regarded it as L. donovani. Similar 





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Fig. 163. — Longitudinal Section of the Intestine and Transverse Section 

 OF A Malpigiuan Tube of the Dog Flea, showing Leptomonas cienocephali 



LINING THE HiND-GUT AND THE MaLPIGHIAN TuBE (x Ca. 170). (ORIGINAL.) 



flagellates have been seen in other fleas, but as far as is known they 

 correspond very closely with L. ctenocephali, and it is not improbable 

 that they may be identical with it. Cross-infection experiments with 

 bred fleas will have to be undertaken before this is finally settled. All 

 these forms belong to the genus Leptomonas, as here defined. 



In the dog flea the infection is limited to the intestinal tract and the 

 Malpighian tubes which open into it just behind the stomach (Fig. 163). 

 Most usually, flagellates do not occur in the stomach, but when the infec- 

 tion is exceptionally heavy, it may extend forwards to this portion of the 

 intestine. As a rule, the infection stops abruptly at the pyloric opening, 

 where a large cluster of free and attached organisms often occurs. The 

 condition in which the flagellates are found in the gut depends to some 



