FEEDING INTESTINAL WUKM.S TO FLIES 313 



opinion that even full-grown larvai' are unable to swallow un- 

 ruptured eggs as large as those of the worms used, namely 

 07 mm. 



Details are given by Nicoll of the most important of his 

 experiments on the feeding of infective material to flies. The 

 material was offered to the flies in four different ways. 1. Faeces 

 containing ova. 2. Complete worms, or intact parts of them. 

 3. Broken or damaged segments of worms. 4. Suspensions of 

 ova in water. After feeding flies were examined at varying 

 intervals ; the bodies and appendages were first examined ; after- 

 wards the alimentary tract was dissected out and examined. The 

 results of his experiments were as follows : 



(a) Hynienolepis diminuta (ova 07 by "005 mm.). 



1. 11 flies were fed on contents of caecum of rat containing 

 numerous eggs. Negative results were obtained. 



2. 12 flies fed on rat faeces containing numerous ova. 

 Negative results obtained. 



3. flies fed on ripe segments of Hymenolepis diminuta 

 containing numerous ova. Negative results. 



4. 6 flies fed on emulsion of tape-worm in water, containing 

 numerous ova. Negative results. 



These experiments demonstrated the inability of Musca do- 

 mestica to ingest eggs as large as those of Hymenolepis diminuta. 



(h) Toxascaris liinhata (ova '08 by '07 mm.). 



1. 8 flies fed on dog faeces containing numerous eggs. 

 Negative results. 



2 and 3. Two lots of G flies each fed on intact and broken 

 female Avorms respectively. Negative results in each case. 



(c) Anki/lostoma caninuni (ova '06 by "04 mm.). 



Negative results were obtained after feeding flies on dog 

 faeces containing ova. 



(d) Trichuris trichiuris (ova '05 by •025 mm.). 



From 12 flies which had been fed on human faeces containing 

 a few ova, the ova of this tape-worm were recovered from one fly 

 and from the faeces of another fly. 



