NO. 15 ARTHROrOD HOSTS OF IIELMTNTIIS HALL I7 



fly evidently plays the role of host for the tapeworm and food for the 

 ralliform bird host. 



PROTEOCEPHALIDAE 



So far as final hosts and intermediate hosts are known, the cope- 

 pods are outstandingly important as intermediate hosts of proteo- 

 cephalid tapeworms in fish, the Cladocera serving as hosts in only one 

 case. Apparently these tapeworms form a procercoid in the entomos- 

 tracan host, and this develops to a second larval stage in small fish or 

 other suitable hosts, and then to an adult when this second inter- 

 mediate host is eaten by a suitable primary host. 



DIPHYLLOBOTHRIIDAE 



In the Diphyllobothriidae we have tapeworms in which the life 

 history sometimes, though apparently not always, involves two inter- 

 mediate hosts. For the known cases, the first intermediate host is 

 always an entomostracan and the second intermediate host is a fish. 

 The known entomostracan hosts are copepods. Since the role of 

 intermediate host played by entomostracans in these life cycles is 

 evidently based on the role of Entomostraca as fish food, it is obvious 

 that the Entomostraca would be first choice as intermediate hosts of 

 diphyllobothrids in a search for the first host, and the copepods 

 would be first choice among the Entomostraca. 



RHYNCHOBOTHRIIDAE " 



The life history is known for only one species of rhynchobothrid 

 tapeworm, and in this case decapod crustaceans serve as intermediate 

 hosts. Additional data are needed before one could safely generalize 

 in regard to the intermediate hosts of tapeworms of the family Rhyn- 

 chobothriidae. 



ARTHROPODS AS INTERMEDIATE HOSTS OF TREMATODES 

 The following list will serve as a basis on which to draw some 

 conclusions as to the role of arthropods as intermediate hosts of 

 trematodes. In assigning flukes to various families, the writer has 

 followed various authorities as there is considerable disagreement in 

 regard to the taxonomy of fluke groups, and the arrangement used 

 will not meet with anything like unanimous approval. It is only 

 intended to serve as a tentative basis for a discussion within the scope 

 of this paper. 



