*242 
Worm ova in Flies 
Meat Market (29-30. xn. 1914). 
Of 25 flies, caught at mid-day, 2 harboured ova as follows: 
Fly No. Tri. d. Ank. d. 
8 2 — 
19 — 2 
Of 25 flies caught in a house in the bazaar and at the hospital about 
6.30 a.m., none were found to harbour ova. The sexes of the flies were 
in the proportion of 21 $ to 4 ?. 
In the lots of flies collected in the other localities to which the 
previous protocols relate, the females were more numerous, all having 
been collected at mid-day; thus of 175 flies collected at the Native 
Hospital, in the Police Lines and Meat Market, of which the sexes were 
determined, 60 were $ and 115 ?. Out of a total of 275 flies, separately 
examined, 29 (= 10 per cent.) were found to harbour ova; this excludes 
the last batch captured in the morning and which was so largely com¬ 
posed of male flies. The females contain worm ova much more frequently 
than do the males, the ratio in the positive results being 15 to 2. 
Whereas the females appeared as if they had recently fed, the males 
showed no such appearance. The discrepancy between the sexes is 
therefore doubtless due to differences in feeding habits. 
Whereas the human faeces showed a high percentage of infection 
with the ova of Ankylostoma duodenale (46 per cent.) and Ascaris lum- 
bricoides (44 per cent.), the ova of these species were only found in 
flies on five occasions and on one occasion respectively. On the other 
hand the ova of Trichocephalus dispar and Taenia saginata which were 
found in 43 per cent, and 29 per cent, of the samples of human faeces 
were encountered on sixteen and eight occasions respectively in flies. 
Finally, Schistosomum mansoni eggs which occurred in 5 per cent, of 
the human faeces examined, were encountered once only in a fly. The 
ova encountered in the flies were in the following order of frequency: 
Trichocephalus dispar (16), Taenia saginata (8), Ankylostoma duodenale 
(5), Ascaris lumbricoides (1), and Schistosomum mansoni (1). It should 
be noted, however, that in the first series of flies from the Native 
Hospital, the examination of the insects was carried out over a period 
of eight weeks during which the ova of Ankylostoma may have suffered 
through putrefaction changes occurring in the imperfectly preserved 
insects. No Ankylostoma ova were found in these flies after the fifth 
day. 
