130 PROCEEDINGS OF THE NATIONAL MUSEUM vol. m 



Body segments finely coriaceous under magnification, without 

 punctations. Segmental sulcus distinct entirely around body, 

 anterior portion of prozonite with fine transverse striae. Pores very 

 small but distinctly in the mesozonite, below level of the lateral longi- 

 tudinal suture. Lower sides with a few longitudinal ridges, not pro- 

 duced into marginal spines; ventrolateral areas of prozonites and 

 mesozonites ornamented with very fine ridges forming elongate poly- 

 gons that merge dorsally into the transverse striae. 



Telson broad and bluntly angular, not concealing valves in dorsal 

 aspect; the latter typical for the subfamily in appearance; preanal 

 scale broadly transverse, entirely smooth and lacking modifications 

 such as occur in Centrelus kerrensis. 



Sternites subrectangular, only slightly narrowing caudad, with 

 about six to eight fine transverse striae laterally turned caudad. 

 Stigmata contained entirely with the sternal sclerite. Legs smooth 

 and polished, the tarsal claw very long and slender, more than half 

 as long as tarsal joint; ventral setal formula 1-1-2-2-2-6; tarsi with 

 two or three small setae on caudal side and one on the cephalic. 



First two leg pairs of the male reduced in size and strongly incrassate, 

 especially the basal two joints. Tarsal claws of first three leg pairs 

 very long, becoming shorter on the next pairs. Coxae of anterior 

 legs not produced or lobed although membranous areas, possibly 

 extrusible to some extent, can be detected when the legs are dry. 



Sympleurite of seventh segment nearly parallel-sided and slender, 

 the median suture visible. Gonopods (figure Q,a,b) with sternite of 

 anterior pair slender, nearly straight across and, on the caudal side 

 of the gonopods, not entirely fused to the coxite, a distal portion being 

 free and somewhat projecting. Coxites somewhat crescentic in shape, 

 in contact with the sternite, and arching mesially, separated by a 

 small slender vinculum, apices of coxites set with areas of fine denticles. 

 Telopodites quite small, with caudolaterally directed apices, the latter 

 not or but slightly visible in anterior aspect. Posterior gonopod with 

 very long and slender apodeme; distal elements not distinctly divided 

 into coxite and telopodite, the caudal margin of the joint produced 

 into a large thin lamina, drawn out distally into an acute hyaline angle. 



Discussion: Variation: The number of segments in four specimens 

 from the type locality ranges from 45 to 48; two males from Baylor 

 County, Texas, have 44 each. However, four specimens from the 

 vicinity of AbUene, Texas, have counts ranging from 48 to 52 and 

 suggest that there may be an east-to-west decrease in segment number. 

 In all of the material examined, the clypeal foveolae vary from 4-4 

 to 5-5. There is considerable variation in size, specimens from the 

 western extremity of the range being smaller but otherwise similar 

 to the larger eastern individuals. 



