586 PROCEEDINGS OF THE NATIONAL MUSEUM vol. ii4 



of bifurcation subacute to narrowly rounded; furcae of medium length, 

 rather robust, tubular, central portions weakly expanded in lateral 

 aspect, sparsely setose, curving ventrad toward apices, rather closely 

 subparallel; apices slightly divergent, directed ventrad, acute. 



Gnathos typically paired, directed ventrocaudad; arms with apices 

 overlapping, glabrous, subacute. 



Anellus membranous, unarmed, juxta absent. 



Aedeagus of medium length and width, asymmetrical, glabrous; 

 base considerably expanded ventrad and partially opening dextrad 

 remainder sublinear; approximate basal half cylmdrical, apical half 

 opening broadly dextrad, apex narrowly rounded. 



Vesica large, membranous, armed along dorsal and apical margins 

 with row of approximately 10-15 cornuti; cornuti minute, acute, 

 closely set, dhected distad. 



Type. — cf and 9 types in the British Museum (Natural History). 



Type locality. — "Arizona." 



DisTRiBUTiojsi . — Southwestern United States. Arizona, New Mexico, 

 and Texas. 



Specimens examined. — 48 (41 cf cf, 7 99), from 13 localities: 



Arizona: Baboquivaria Mountains, 2 cf c?" (no date, F. H. Snow); Huachuca 

 Mountains, 9 (July 20, 1936, J. N. Knull) ; McNary, White Mountains, 2 c?" cf 

 (July 10, 1936, A. B. Klots collection); Nogales, cf (Aug. 27, 1906, A. Koebele); 

 Patagonia, 10 cf cf , 9 (July 18, 1948, C. & P. Vaurie) ; Pinal Co., "6 miles south 

 of Florence," cf (July 23, 1924, E. P. Van Duzee) ; San Bernardino Ranch, 

 Cochise Co., 3 c? c?" (Aug., elevation 3750 feet, F. H. Snow) ; San Carlos, 9 

 (July 11, 1936, "Parker, Lot 306," A. B. Klots collection); Tucson, 5 cf cf , 9 

 (St. Xavier National Monument, July 29, 1924, E. P. Van Duzee and J. O. 

 Martin), d^, 9 (July 30, 1937, A. B. Klots), S d" d" (Oct. 8-10, 1939, Crandall), 

 2 c?" cf (July 18 and 29, 1943, Fred H. Rindge collection); Tumacacori National 

 Monument, Santa Cruz Co., 4 cf c?", 9 (July 20, 1948, C. & P. Vaurie). New 

 Mexico: State College, 5 d' c? (July 8, 1945), cf (July 26, 1945). Texas: Davis 

 Mountain Junction, Reeves Co., cf (July 10, 1948, C. & P. Vaurie); Marathon, 9 

 (July 9, 1948, C. & P. Vaurie). 



Remarks. — The material studied for this species was received on 

 loan from six sources. The American Museum of Natural History 

 furnished about half the specimens. 



A. arizonellus, which undoubtedly ranges southward into Mexico, 

 is very closely related to luriei, the two comprising a small species 

 group. This group is related to those acrolophids having elongate 

 labial palpi, setose eyes, bifid uncus, and paired gnathos. However, 

 luriei and arizonellus may be distinguished from each other and from 

 the other species treated here on the basis of their harpes and aedeagi. 

 In arizonellus, the sacculus of the harpe is strongly angulated at its 

 ventrocaudal extremity, a condition not exhibited by luriei. In 



