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bulo iire nalurally inlected with a flag'ellate wliich is identical 
wilh H erpctomonas muscae domcsticae, Burnett. 
After examining several tliousand specimens of lhe Madras 
bazaar l'iy, I foiind that practically loo % caiight in tlie méat 
shops were infected with Herpetomonas miiscac domesticae, in 
fact it was rümost impossible to find an iininfected fly in any of 
the man\' batches examined. The flagellâtes were commonly found 
in large numbers and represented many of the developmental sta¬ 
ges of the parasite ; adult flagellâtes exhibiting ail the varions 
phases of simple longitudinal division, encysting forms, as well 
as the ripe cysts, were ail to be found in the alimentary tract 
of the same fly. In addition the typical long flagellâtes and the 
short encysting forms (post-flagellate stage) were comimonly seen 
in coLintless numbers in the fluid excreta of a large percentage 
of the bazaar flies. The study of the parasite in these flies was 
found however to be most unsatisfactory, as it was not possible 
to say definitely what stage of the infection any particular para¬ 
site or group of parasites represented, and no adéquate explan- 
ation could be given to account for the intense infections en- 
countered. I therefore decided to breed flies and to endeavour to 
infect them in the laboratory. 
Eggs of the flies were daily placed in fresh horse dung so that 
every day a large number of adult insects were available for use. 
Each batch of pupae were placed at the bottom of glass jars to 
which were attached tin frames covered with mosquito netting 
(PI. 1 , fig. 1 ). Each jar with its cage was enclosed in a bamboo 
frame also covered with mosquito netting (fig. 2), thus allowing a 
space of one inch between the netting containing the flies and 
that of the outer frame. This précaution was taken in order to 
prcvent wild flies from coming in contact with the caged insects. 
Before being used, each jar with its tin frame and mosquito net¬ 
ting was washed in 1-20 carbolic acid, and then dried in the sun, 
so that everv précaution was taken to prevent the caged flies from 
becoming infected except in the desired way. 
After examining a large number of bred flies fed on clean 
food and kept in the cages described above, no evidence of hered- 
itarv infection was found. Ilereditary transmission in this case 
must mean that the parasites pass through the varions stages of 
the flv, but thev hâve never lieen found in larvae bred in horse 
dung: the long flagellâtes hâve however been seen in very 
