438 ARACHNIDA CHERNETIDEA chap, xvi 



running backwards or sideways with their pedipalpi closely 

 folded up against the body. Four genera usvially admitted fall 

 within this group : — Ohisium, Eoncus, Blothrus, and Chthoniios. 



Ohismm has four eyes, parallel - sided cephalothorax, and 

 curved chelae on the palps. Roncus is like Ohisium except in 

 having only two eyes, and is therefore disallowed by Simon, who 

 also considers Blothrus to comprise merely eyeless species of 

 Ohismm. In ChtJwnius the cephalothorax is broadest in front, 

 and the digits of the chelae are straight. 



The Obisiinae are found in moss and debris, and under stones. 

 Three species of Ohisium, two of Roncus, and four of Chthonius 

 are recorded in England. 



The subjoined list of British species of Chernetidea is taken 

 from the monograph of the Eev. O. P. Cambridge, cited above : — 



Group I. — Four eyes. 



ChtJwnius orthodactylus, Leaoli. 

 „ rayi, L. Koch. 

 ,, tetrachelatus, Preyssler. 

 „ tenuis, L. Koch. 

 Ohisium muscorum, Leach. 



„ sylvaticuw, C. L. Koch. 

 „ maritimmn, Leach. 



Grodp IL — Two eyes. 



Boncus cambridgii, L. Koch. 



„ lubricus, L. Koch. 

 Chelifer hermannii. Leach. 



„ cancroides, Linn. 



„ meridianus, L. Koch. 



„ suhruher, Simon. 



,, latreillii, Leach. 



Gboup III. — Xo eyes. 



Chernes nodosus, Schr. 



„ insuetus, Camb. 



„ cimicoides, Fabr. 



„ dubius, Camb. 



„ phaleratus, Simon. 

 Chiridium museorum, Leach. 



