212 BRITISH SPECIES OF FALSE-SCORPIONS. 



GEN : OBISIUM (Leach). 



Cephalothorax, as broad as long, sometimes longer than broad, 

 and as wide before as behind or slightly narrower in front. Eyes 

 rather large or moderate size ; the anterior eye on each side is near 

 to but separated from the fore-margin of the caput, and the interval 

 between the two eyes on each side is distinct, but not equal to a 

 diameter. Tarsi of the two first pairs of legs sub-divided. Trochantin 

 indistinct in the third and fourth pairs. Abdominal plates as in 

 Chthonius. Falces strong, but not as long as the cephalothorax. 

 Claws of the pincers curved, as long or longer than the bulb. The 

 Cephalothorax, abdomen, &c., are furnished with simple hairs ; the 

 integument very smooth and shining. 



Three species only are as yet certainly recorded in Britain ; 

 0. muscorum (Leach), 0. sylvaticum, and 0. maritimum (Leach). 

 These may be distinguished as follows : 



i. Claws of pincers long, not so strong ; more strongly 

 curved, and considerably longer than the bulb. 



0. muscorum (Leach). 



ii. Claws of pincers short, strong, slightly curved, and scarcely 

 equal, or no more than equal to the bulb in length. 



a. Bulb very robust; humeral joint of pulpus 



shorter in proportion. 0. sylvaticum. 



b. Bulb less robust, of a more oval form ; humeral 



joint longer in porportion to the cubital. 



0. maritimum. 



OBISIUM MUSCORUM. PI. A, fig. 1, and B, fig. 6. 

 Syn : OUsium muscorum (Leach). Zol. Misc. in., p. 51., pi. 



144, fig. 3, 187. 



OUsium simile (L. Koch). Darst. Eur. Chernet, p. 58, 

 1873, and E. Simon, Arachn. de France, torn. 7, 

 p. 58, 1879. 

 0. muscorum (Leach). Dale, Hist., Glanvilles Wootton, 



p. 325. 

 Length IJrd to 1J lines. 



