Ewing — Significance of Parasitism in Acarina. 59 



tion of the general classification given for all parasites 

 in the introductory chapter. 



A Classification of the Parasitic Acarina Based 



Upon the Different Aspects of 



Parasitism Presented. 



Taking into account the nature and habits of the para- 

 sites themselves. 



Depending upon the nature of the food eaten. 

 Living upon the bodily tissues. 

 Living upon live tissues. 

 Gen. Harpyrhynchus. 

 Sarcoptidae (itch mites). 

 Gen. Laminosioptes of the Cheyletidae. 

 Living upon dead tissues. 



Analgesidae (bird mites). 

 Listrophoridae. 



Canestrinidae (?). These forms doubtless live upen 

 live tissues also. 

 Feeding upon partially digested food. 

 Antennophorus. 

 Echinomegistus wheeleri (?). 

 Living upon blood. 



Parasitic larvae of Rhyncholophldae, Trombldildae, 



Hydrachnidae and Halacaridae. 

 The ticks, Ixodldae and Argasidae. 

 Dermanyssldae. 

 Haemogamasus and RaiUietia of the Gamasids; CiJli- 



bano (?). 

 Some species of Pediculoidea. 

 Some species of Cilliba, a genus of the Uropodldae. 

 Feeding upon secretions. 



Cytoleichus (?). It probably feeds both upon mucous 



secretions and the cellular fluids of Its host. 

 Demodex. The species of this genus live largely upon 



the oil secreted in the hair follicles. 

 Myobia. Species of this genus feed at the bases of hairs 



of mammals upon cutaneous excretions. 

 Oolaelaps oophilus. (Lives upon the salivary secretion 

 with which some ants coat their eggs.) 

 Living upon eggs. 



Genus Hemisarcoptes. It lives upon eggs of scale In- 

 sects (predaceous?). 

 'Bistiostoma berghi, lives in egg capsule of a horse-leech. 

 Larvae of some of the Halacaridae. 



