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By C. D. Soar. Part IX. Plates XII. and 



LL the species of Hydrachnidce which have been 

 mentioned in my former papers belong to the 

 sub-faraily Lateroculat^. The two acarids which 

 will form the subject of this paper belong to the 

 sub-family MEDiocuLAXiE (Haller), which contains 

 two genera only : — Limnocharis and Eylais. Mr. 

 Michael, in his British Oribatidce, page 50, gives a 

 key to the families of the Acarina, in which he 

 includes the Halicarince with the Lim7iocaridce^ and 

 on page 49 he says : — " I have some doubt about my own cor- 

 rectness in including the Halicaridce among the Limnocaridce ; but 

 I think on the whole that they are fairly placed together." 



Now the Halicaridce are Marine mites, or are generally looked 

 upon as such, but I believe several species are found in fresh 

 water. Anyone interested in this family will find a lot of informa- 

 tion in a small book by Hans Lohmann, Jena, 1888 — Die Unter- 

 fa77iilieder Halacarides Micrr^ which has at the end a Bibliography of 

 sixty-one papers on the subject. At present I have nothing to say 

 about Marine mites, so I will confine the few^ remarks I have to 

 make to the two genera above mentioned — Linmocharis and Eylais. 

 Each of these two genera, I believe, are up to the present date 

 only repres^ted by one species each. The distinguishing features 

 of these are so great that they cannot, when once known, be mis- 

 taken one for the other, or for any other species of another genus. 

 Both have their eyes near the centre line of the body. Both are 

 red and both attain a large size. In both, also, the mouth organs 

 are modified into a sucker-like tube, but here the similarity ends, 

 for one is a swimming mite and the other is a crawler. 



Genus X. — Eylais^ Latreille. 



1796. — Eylais, Latreille. Precis des Caracthes des Insectes, p. 182. 



Body, oval ; eyes, approximated to the median line of the 



body ; the fourth pair of legs without swimming-hairs. 



iNTERNArioxAL Journal of Microscopy and Natural Science. 

 Third Series. Vol. VII. p 



