438 ARACHNIDA—CHERNETIDEA CHAP. XVI 
running backwards or sideways with their pedipalpi closely 
folded up against the body. Four genera usually admitted fall 
within this group :—Obisium, Roneus, blothrus, and Chthonius. 
Obisium has four eyes, parallel-sided cephalothorax, and 
curved chelae on the palps. Ronews is like Obisiwm except in 
having only two eyes, and is therefore disallowed by Simon, who 
also considers Blothrus to comprise merely eyeless species of 
Obisium. In Chthonius the cephalothorax is broadest in front, 
and the digits of the chelae are straight. 
The Obisiinae are found in moss and débris, and under stones. 
Three species of Obisiwm, 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 Rev. O. P. Cambridge, cited above :— 
Group I.—Four eyes. 
Chthonius orthodactylus, Leach. 
“3 rayt, L. Koch. 
- tetrachelatus, Preyssler. 
5 tenuis, L. Koch. 
Obisium muscorum, Leach. 
»  sylvaticum, C. L. Koch. 
a maritumum, Leach. 
Grover II.—Two eyes. 
Roncus cambridgi, L. Koch. 
»  lubricus, LL. Koch. 
Chelifer hermannii, Leach. 
»  cancroides, Linn. 
»  meridianus, L. Koch. 
5 subruber, Simon. 
»  latreilliz, Leach. 
Group III.—No eyes. 
Chernes nodosus, Schr. 
»  wmsuetus, Camb. 
»  evmicotdes, Fabr. 
»  dubius, Camb. 
»  phaleratus, Simon. 
Chiridiwm museorum, Leach, 
