62 Trans. Acad. Sci. of St. Louis. 



Taking into account tlie interrelations of the parasites 

 and organisms affected. 



Depending upon the position of the parasites In relation to their 

 hosts. 



Endoparasites. 



Sarcoptldae (In part), 

 Cytolelchldae (?). 

 Demodecidae (?). 

 Ectoparasites. 

 Cuticolata. 



Harpyrhynchus, Psorergates. 



Gekobia, 



Larvae of Rhyncholophldae, Trombidildae, Hydra- 



chnldae, Halacarldae. 

 Ixodldae. 



Parasitic Tarsonemldae. 

 Sarcoptldae (mostly). 

 Cytolelchldae (?). 

 Demodecidae. 

 Vlllicolata. 

 Myobia. 

 Listrophorldae. 

 Plumlcolata. 



Picobia, Syrlngophilus. 

 Analgesldae. 

 Depending upon the duration or time of parasitism. 

 Erratic parasites. 



Semiparasitic Tetranychidae. 

 Atax (?). 



Some of the Gamasidae and some of the Uropodldae. 

 Some of the Tarsonemldae. 

 Hemisarcoptes. 

 Periodical parasites. 

 Nocturnal. 



Argasldae. 



Dermanyssldae (in part). 

 Diurnal. 



(Data upon habits in this regard wanting.) 



During a definite stage or stages In the life cycle 

 of the species attacked. 

 During the egg stage. 

 Histiostoma berghi. 

 Hemisarcoptes. 

 During the fetal stage. 

 During the immature stage. 

 Pediculoides ventricosus. 

 During adult stage. 



