1904.] NATURAL SCIENCES OF PHILADELPHIA. 309 



resemblances to Aidonia. All the species of Pirata known to me live 

 beneath stones close to water, and spin for themselves during the cold 

 season little closed nests. 



Key to Species of Pirata. ' 



a. 1. — Eyes of the second row not more than one-half their diameter 

 apart, chelicera with 2 teeth on the posterior margn, , marxi. 

 a. 2. — Eyes of the second row nearly or quite their diameter apart, 

 chelicera with 3 teeth on the posterior margin. 

 b. 1. — Sternum blackish with a yellow median band and 3 yellow 

 spots on each side, cephalothorax of the 9 only one- 

 quarter longer than broad, prodigiosus Keyserling, 1876. 

 b. 2. — Sternum not so colored, cephalothorax in the 9 one-half 

 longer than broad. 

 c. 1. — Venter with dark bands or rows of dark spots, femora 



usually distinctly annulated, liber. 



c. 2. — Not so colored. 



d. 1. — Legs almost devoid of hairs, . . . elegans, 

 d. 2. — liCgs covered with fine soft hairs. 



e. 1. — A large dark spot at each side of the spin- 

 nerets, ? with leg IV 3.3 times the length 

 of the cephalothorax, . nigromacidatus. 

 €. 2. — No such black spots, $ with leg IV 4.4 times 

 the length of the cephalothorax, 



sedentarius. 



Pirata marxi Stone. PI. XIX, fig, 27. 



Pirata marxi Stone, 1890. 

 Pirata marxi Stone, Montgomery, 1902. 

 Pirata piraticus Clerck, Emerton, 1S85. 

 nee Pirata piraticus Clerck. 



( ? ) type, Pennsylvania; 9 from Massachusetts.) 



Eyes. — First row fully as broad as the second, straight, nearer the 

 second row than the margin of the clypeus, the middle eyes only slightly 

 larger than the lateral. Eyes of the second row one-half their diameter 

 apart. Length of dorsal e3^e area to cephalothorax as 1 : 5.5. Quad- 

 rilateral of the posterior ej'es much wider than long. 



Form. — Cephalothorax without hairs, highest behind the posterior 

 eyes, posterior declivity very abrupt and steep, in front one-half its 

 greatest transverse diameter. Chelicera with 3 teeth anteriorly and 

 2 posteriorly, rather straight anteriorly, their length greater than the 

 width of the clypeus and about twice the height of the head in front. 

 Labium longer than Inroad and more than one-half the length of the 

 maxillse, broadest behind its middle, rounded apically. Sternum large, 

 nearly round. Length of leg IV to cephalothorax as 3.8 : 1; meta- 

 tarsus IV shorter than patella and tibia combined by one-half the 



