Ewing — Significance of Parasitism in Acarina. 61 



Zoophaga. 



Tarsonemidae (in part). 



Listrophoridae. 



Analgesidae, Canestrinidae, Sarcoptidae, Cytoleichidae. 



Demodecidae. 

 Depending upon the conditions imposed by the life of the host. 

 Hydroxenous. 



Larvae of Hydrachnidae and Halacarldae. 



Gen. Atax. 

 Geoxenous. 



MyoMa and Psorergates. 



Gekohia. 



Ixodidae, Dermanyssidae (in part), parasitic Gamasidae. 



Cilliha. 



Parasitic Tarsonemidae. 



Listrophoridae (in part). 



Canestrinidae. 



Sarcoptidae (mostly). 



Cytoleichidae. 



Demodecidae. 

 Aeroxenous. 



Harpyrhynchus, PicoMa and Syringophilus. 



Larvae of Rhyncholophidae and Trombidiidae. 



Argasidae, Dermanyssidae (In part). 



Listrophoridae (in part). 



Analgesidae, some of the Sarcoptidae. 

 Depending upon the number of host species. 

 With a single host species. 



Parasitic Cheyletldae (in part). 



GekoUa (?J. 



Cilliba (?). 



Listrophoridae (In general). 



Analgesidae (in part). 



Canestrinidae. 



Sarcoptidae (in general). 



Cytoleichidae (?). 



Eriophyidae (in part). 

 With more than one host species. 



Parasitic Tetranychldae. 



Larvae of Rhyncholophidae, Trombidiidae, Hydrachni- 

 dae and Halacarldae (in general). 



Ixodidae, Argasidae, Dermanyssidae and parasitic 

 Gamasidae. 



Parasitic Tarsonemidae. 



Analgesidae (in general). 



Sarcoptidae (a few species). 



Demodecidae (?). 



Eriophyidae (in part). 



