314 THE SPREAD OF INTESTINAL WORMS BY FLIES 



(e) Dipylidium cauinuni (ova 'O^ by "04 min.). 



1. 4 Musca and 1 Fannia were fed on unbroken ripe segments 

 of the worm. The eggs were recovered from 2 Hies {Musca) 26 

 hours after the infected faeces had been removed, demonstrating 

 the ability of the flies to suck the eggs of the tape-worm and to 

 carry them for a considerable time. 



2. 6 flies were fed on dog faeces containing ova. The ova 

 were found in 4 of these flies ; in the case of 2 of the flies 43 

 hours after the infected faeces had been removed, showing that 

 the flies can carry the eggs in their intestines for at least that 

 length of time. 



( /') Taenia marginata (ova "035 by '035 mm.). 



1. The eggs of this species were removed from a blow-fly 

 (Calliphora) on the second day after it had been fed on mashed 

 up segments containing ova. 



2. Eggs Avere recovered from Musca and Fannia nearly three 

 days after they had fed on ruptured segments containing numerous 

 ova. 



3. Eggs were recovered from Musca the day after it had fed 

 on an emulsion of ripe segments. 



((/) Taenia serrata (ova -035 by -035 mm.). 



1 and 2. Eggs were found in flies in very large numbers, 500 

 in 3 flies and 400 in 2 flies, 2 hours after feeding on ripe segments 

 in water, and on ruptured segments. 



3. Eggs were found in a fly 21 hours after feeding on intact 

 segments containing numerous ova. 



4. Negative results were obtained from 4 flies fed on dried 

 segments. 



0. A single egg was recovered from one of 7 flies 8 hours 

 after they were fed on intact segments containing numerous ova 

 and one egg was found in the flies' faeces about 20 hours after the 

 segments had been removed. 



6. From 3 flies which had fed on an emulsion of segments 

 containing numerous ova, 1, 22 and 312 eggs respectively were 

 recorded up to 7 hours after the emulsion had been removed. 



