90 THK CANADIAN ENTOMOLOGIST. 



KEY TO THE FAMILIES OF SPIDERS OF THE U. S. 



j Fang moving vertically, usually two pairs of lung slits . . 

 { Fang moving horizontally, but one pair of lung slits . . 



2 



I Cave spQcies 3 



[ Not cave species 5 



J Six eyes, in three groups of two each, body round DysderidoE 



^ \ Eyes not so arranged, body more elongate 4 



f Two claws to tarsi Chcbionidce 



'^ I Three claws to tarsi . . . Theridiidce 



j Eyes six 6 



^ ) Eyes eight 9 



, f A pair of stigmata just caudad of the lung slits Dysderidce 



\ No stigmata close to lung slits 7 



f The six eyes in three groups of two each Scytodidce 



' \ The six eyes in two groups of three each 8 



„ I Legs very long and slender ( Spermophora) Pholcida 



\ Legs short ( Neophanes) Didyfiidce 



Cephalothorax produced in front of pars cephalica, which is very small, 

 maxillae closely surrounding the lip, mandibles small, cephalo- 

 thorax roundish i o 



Not such spiders 12 



f S. E. touching Pho/cidce 



\ S. E. separated, P. S. E. and P. M. E. touching 11 



( Apex of abdomen surrounded by a circle of bent hairs .... Urodeidce 

 \ Abdomen without such hairs FilistatidcB 



( Eyes equal or subequal, often dissimilar *, more or less in two rows 

 ) variously curved, forming a group much wider than long. ... 20 

 1 Eyes unequal, similar, in three or four rows, forming a group almost 

 \ as long or longer than wide 13 



\ With a calamistrum and cribellum (Hyptiotes) Uloboridie 



^ \ Without calamistrum or cribellum 14 



I Largest eyes in anterior row 15 



^ \ Largest eyes not in anterior row . 16 



j Eyes in three rows Attidce 



^ \ Eyes in four rows Lyssomanidce 



, j Two claws to tarsi, only two eyes in anterior row Ctenidce 



\ Three claws to tarsi 17 



* Dissimilar = eyes of two colours, dark and light ; similar— eyes of but one colour. 



10 



II 



12 



