508 CLASS ARACHNIDA. 



of eyes varies fi'om two to four, and goes even as far as six, 

 according to Muller. 



The mouth of the species, which I have studied, presents 

 the three following modifications, which have served as bases 

 for three generic sections, but to which it is impossible to 

 refer all the species of Muller's Hydrachnse, this naturalist 

 not having described them with sufficient detail. 



Eylais, Lat., 

 Which have antennae-pincers, terminated by a mobile hook. 



Hydrachna, Lat., 



Whose mouth is composed of laminae, forming an advanced 

 sucker, and whose palpi have under their extremity a mobile 

 appendage. 



LiMNOCHARES, Lat., 



Similar to hydrachna, in the sucker-formed mouth, but whose 

 palpi are simple. 



Other Mites, Microphthira, Lat., are remote from all 

 the other aranchnides, by the number of feet, which is only six. 



They are all parasite. 



Caris, Lat., 



Which have a sucker and apparent palpi ; the body rounded 

 very flat, and clothed with a scaly skin. 



Leptus, Lat., 



Having also a sucker, and apparent palpi, but whose body is 

 very soft and ovoid. 



L. Autnmnalis, Acarus Autumnalis, Shaw, Zool., Misc. 

 t. IT. pi. xlii., a species very common in autumn, on gra- 

 mineous and other plants. It climbs and insinuates itself 



