NEMATODE PARASITES OF BIRDS 393 



suborder, the Trichurata. A study of these groups is much needed 

 but was not considered possible in the scope of the present paper. 



The author has made several new superfamilies and families in 

 order to coordinate the groups below them. The nematodes treated 

 in detail fall into 5 superfamilies; there are approximately 50 genera, 

 containing a total of about 500 species. About two-thirds of this 

 material falls in the Spiruroidea and the emphasis has accordingly 

 been placed on that superfamily. Due to the heteroxenous nature of 

 the spirurids and the food habits of many birds, which insure the 

 latter coming in contact with the intermediate hosts, an opportunity 

 is afforded for a rich variety of parasitic nematodes of this type. 

 The usual intermediate host of the spirurid is an arthropod; these 

 arthropods are eaten by insectivorous birds in the case of insects and 

 by water birds in the case of entomostracans, and a completion of 

 the life cycle ensured. Birds of prey may possibly derive their 

 spirurid parasites from rodents or other small animals in which the 

 larvae have encysted as so-called "aberrant " forms. Doubtless many 

 insect hosts are eaten incidentally and accidentally by birds which 

 are not classed as insectivores, when these feed on plant or animal 

 food in which insects are present, and some of these cases may be 

 of a nature suitable for the common transmission of parasitic worms. 



Diagnoses and keys are given in the present paper to all groups 

 from species to orders, inclusive. The descriptive material of each 

 species includes s^ynonyms, hosts, location, morphology, life history 

 and distribution. There are several hundred illustrations copied 

 from the publications of other authors. Several species, the data 

 concerning which were previously incomplete, have been redescribed 

 and figured by the author ; new names have been given to two species 

 (in the genera Heterakis and Hartertia) which were misdetermina- 

 tions by the original describer or have in other ways become con- 

 fused with other species; various species have been allocated to 

 genera other than those in which they had previously been placed. 

 Seven new species have been added ; six of these are spirurids, falling 

 in the genera Cyrnea, C heilospincra, Hartertia, Echinuria, Tetra- 

 meres, and Mierotetrameres ; the sixth is a heterakid. 



It is hoped that the collecting of the widely scattered material, 

 published previously in many different countries and many different 

 languages, after having been translated, systematically arranged and 

 as far as possible critically analyzed, will prove of value to other 

 workers in the field of parasitology. 



LIST OF HOSTS AND THETR PARASITIC NEMATODES 32 



The writer is greatly indebted to Dr. H. C. Oberholser of the Bio- 

 logical Survey, United States Department of Agriculture, for deter- 



32 See also Addenda (pp. 383-392) for recent reports not included in this list. 



