238 



PARASITES OF FIJES 



experiments in the hot weather of 1907, when flies were abundant in Madras, and as 

 a result was able to study the early development of the parasite in the mid-gut of the 

 fly."..." The majorit)' of adult flagellates have the appearance of a double flagellum 

 as figured by Prowazek, but this can only represent the commencing division of the 

 flagellates." 



It is generally believed that in addition to other methods of 

 transmission the flagellates actually penetrate the ova of their 

 host and infect the second generation. Patton's experiments 

 with a bug, Lygceus miiitaris, lead him to think that "the 

 infection is contaminative and not hereditary." 



Fig. 30. Formation of the post-flagellate stages of Hcrpelomonas calliphorcE. 



I. Normal flagellate becoming smaller with short flagellum. 2-5. Elimination of the 

 achromatic part of the blepharoplast. 6-7. Last stages before the production 

 of "cysts." 8-10. "Cysts" without a cyst-wall; Fig. 9 shows a "cyst" with 

 double rhizoplast. 1 1. "Cyst " with a " cyst- wall." 



(Figs. 28-30 are from Swellengrebel, Parasitology, 1911, p. 1 18.) 



Wenyon (191 2, p. 332) recently found that a large pro- 

 portion of house-flies in Bagdad harboured Herpetomonas. 

 The larger parasites he identified as H. viiisae-doviestiav, and 

 the smaller as Leptonionas, a flagellate described by Flu. As he 

 says, the latter may be a distinct flagellate as Flu claims, or it 

 may be a stage in the life-cycle of H. vmscte-douiestiae. 



L^ger (1903) found H. muscce-domesticcE in F. scalar is and 

 P. rudis. Mackinnon (19 10) discovered a species resembling 



