Vol. 35, pp. 11-12 March 20, 1922 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



TWO NEW AMERICAN ARACHNIDS OF THE ORDER 



PEDIPALPIDA. 



BY RALPH V. CHAMBERLIN. 



The two new pedipalpids described below belong to the 

 family Schizomidae, formerly known as the Schizonotidae, a 

 name not tenable because its type genus, Schizonotus, is pre- 

 occupied. The types of the new forms are in the Museum of 

 Comparative Zoology at Cambridge. 



Stenochrus, gen. nov. 



Anterior division of carapace narrow and high, narrowed toward each 

 end from the middle. Posterior division of carapace depressed, consisting 

 of one piece which is not divided by a median longitudinal suture and 

 presents anteriorly no separate lateral sclerites (mesopeltidia). Flagellum 

 three jointed. 



Genotype. — S. portoricensis, sp. nov. 



Differing from Schizomus in its narrow, high carapace, the absence of 

 mesopeltidia, and the three jointed flagellum. Differs from Trithyreus in 

 the absence of mesopeltidia and in lacking a median suture in the posterior 

 division of carapace. 



Stenochrus portoricensis, sp. nov. 



Body somewhat dusky fulvous, sometimes of a slightly reddish cast; 

 terminal joints of abdomen and distal joints of legs more yellow. 



With no trace of eye-spots. Anterior sternum about three-fourths as 

 wide as long. Second thoracic tergite without trace of a median longi- 

 tudinal suture and with no pale line in its place. 



Trochanter of palpi with anterior inferior angle not produced, rectangular, 

 sometimes a little less and sometimes a little more; convex ventral surface 

 obUque, the ectal edge of the oblique surface fringed with setae, the mesal 

 edge with setae and at its distal end with the usual short spine. Femur of 

 palpi not quite twice as long as deep; its inferior edge very obtusely angled, 

 the apex of angle about equidistant from ends of upper side; without pro- 

 cesses. Patella with dorsal margin two and a half times as long as the 

 depth; unarmed. Claw half the length of the tarsus (upper margin). 



Coxa of first legs ending distinctly caudad of distal end of endite. Femur 

 shorter than patella (about as 22 : 25) and a little longer than the tibia 

 4— Proc. Biol. Soc. Wash., Vol. 35, 1922. (11) 



