NEW WESTERN SPIDERS 



By Ralph V. Chamberlin. 



Most of the new forms of spiders described below were 

 found in collections made by the writer in Utah in the latter 

 part of August and the early part of September, 1917. The 

 collections were made on Chalk Creek in the Uintah Mts., 

 at elevations of from 7,300 to 10,000 ft. and at and near Fill- 

 more, Millard Co. In addition to the spiders from Utah, a 

 number of new forms from other localities noted while identi- 

 fying the collections mentioned are here described. 



DICTYNID^. 



Amaurobius utahensis sp. nov. 



Male — Caraijacc, sternum, labium, endites and legs yellow, without 

 any reddish tinge, the legs unmarked. Abdomen blackish, the anterior 

 middle region of dorsum obscure yellow, the posterior half with dark 

 marks which are, excepting the first ones, only vaguely separated 

 from each other. Anterior row of eyes procurved; medians close 

 together, but more than their diameter from the laterals. Posterior 

 eyes much smaller than the anterior ones, the medians slightly smaller 

 than the laterals, about twice their diameter apart and about twice 

 as far from the laterals. Area of median eyes rectangular, being as 

 wide behind as in front, longer than wide. Distal joints of palpus 

 heavier than in nevadensis. Tibial apophyses very similar to those of 

 the species mentioned; but the exterior one distally less uncate, the 

 median one basally broader and more narrowed distad, and the mesal 

 one obviously broader and shorter and differing particularly in being 

 united with or carried forward on a common base with the median 

 one m^uch farther, the ridge uniting the two in nevadensis being slight 

 or obsolete. 



Length. 11.5 mm. Length of cephalothorax, 6.1 mm. Length of 

 tib. + pat. I, ().4 mm.; of tib. + pat. IV, ().7 mm. 



Type— M. C. Z. 414, Utah: Fillmore. 



This species is nearest A. nevadensis Simon. It is a more 

 robust species, wholly lacking the reddish cast characteristic 

 of nevadensis. It differs chiefly otherwise in the details of 

 the male palpus as indicated above and also presents minor 

 differences in the eyes. 



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