CESTODE INFECTION IN CHICKENS 219 



In other kinds of poultry more has been done on the life his- 

 tories of their eestodes. The life cycles of five species of duck 

 cestodes have been demonstrated through experiment. Schmidt 

 (1894) proved that Drepanidotaenia anatina (Krabbe) has its in- 

 termediate stage in a fresh-water crustacean (Cypris ovata). He 

 fed large quantities of tapeworm eggs to the crustaceans and found 

 that the larvae developed in two weeks during the summer. Ros- 

 seter (1891, 1892) has shown that a second duck cestode, Echino- 

 cotylus Rosseteri (Blanchard), has its intermediate stage in an- 

 other small fresh-water crustacean (Cypris cinereus). He fed large 

 numbers of the crustaceans to ducks which upon examination later 

 yielded a large crop of tapeworms of the species named. 



Jlosseter (1897) also demonstrated experimentally the life his- 

 tories of three other species of duck cestodes. He had discovered 

 some cysticerci in crustaceans which he compared with the adult 

 <vorms occurring in ducks and found that they agreed closely. He 

 produced Dicranotaenia coronula in a duck by feeding it Cypris 

 cinerea. Drepanidotaenia gracilis was introduced into the ducks 

 through Cypris cinerea and Cypris viriens. Drepanidotaenia 

 temiirostris was likewise raised by feeding Cyclops agilis. 



As in other cases the question of control of infection in chickens 

 depends to a great extent upon the life history of the parasites. 

 Little can be done to wipe out the disease until more is known of 

 its source. Certain methods may be employed to check it, but as 

 yet it has been impossible to prove the exact source of infection. 

 Usually it is easiest to control such forms during the developmental 

 stages. 



This paper is the result of some investigations carried on to 

 find out the life history of certain chicken tapeworms. Numerous 

 experiments were tried on various insects and many observations 

 made on the habits of the birds in the endeavor to ascertain where 

 the cause of the infection was located. The habits of the birds are 

 probably the chief factors to be dealt with in experiments of this 

 kind. Certain insects that are common about the habitats of the 

 birds are readily eaten. They are hence more likely to be inter- 

 mediate hosts than those which are rare in these localities. Such 

 factors have been taken into consideration and through experiment 

 it has been shown that one cestode, Choanotaenia infundibuli- 

 formis, has its intermediate stage in the common house-fly. 



The most of the material was collected, and the experimental 



