T. O. Shircore 
243 
The small number of Ascaris lumbricoides eggs found in the flies is 
doubtless due to their large size (short diameter 45/x) preventing their 
being swallowed by the flies, this being in agreement with the observa¬ 
tions of Graham-Smith, who fed flies with food containing particles of 
different sizes. The ova of Trichocephalus dispar, judged by their 
appearance, withstand putrefaction in dead flies for nearly two months; 
the ova of Taenia saginata are less resistant in this respect. 
The observations herein recorded indicate a method whereby pre¬ 
valence of helminthiasis may be determined in a locality where it is 
either difficult or impossible to obtain faecal material for examination. 
There should be no difficulty in capturing the flies and preserving them 
in such a manner as to render their subsequent examination possible 
when leisure and opportunity permit. 
