Spiders and Their Near Relatives 



A. With no eyes. A cave species described from Virginia. 



Obisium cavicola 

 AA. With four eyes. 



B. Tibia of palpus with the inner side first convex, then 



nearly straight, fingers longer than the hand. 



C. Hand about twice as long as broad. A large species 



measuring one eighth inch in length. Described 



from North Carolina. Obisium carolinensis 



CC. Hand one and one half times as long as broad. A 



small species common in the Northern States. 



Obisium brunneum 

 BB. Tibia of palpus with inner side evenly convex. 



C. Fingers very much longer than the hand. Found in 



southern California. Obisium macilentum 



CC. Fingers a little shorter than the hand. Supposed to 



have been found in Florida. Obisium parvulum 



Genus BLOTHRUS (Blo'thrus) 



Our only species of this genus, Blothrus calif ornicus , occurs 

 in California. 



Genus CHTHONIUS (Chtho'ni-us) 



This and the following genus are remarkable for the great 

 size of the chelicerae (Fig. 48). 



Six species of this genus have been 

 found in this country, they are separated 

 as follows: 



BB. 



Fig 48. CHTHONIUS 

 MjESTUS 



A. With only two or with no eyes. 



B. Hind legs about twice as long as the 

 abdomen. Found in caves in 

 Kentucky and in Indiana. 



Chthonius packardi 

 Hind legs not much longer than 

 the abdomen. A cave species found in Virginia. 



Chthonius coccus 

 AA. With four eyes. 



B. Cephalothorax and chelicerae with small spines, each 

 tipped with a hair. Found in Florida. 



Chthonius spinosus 



52 



