336 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 117 



of 2nd legs with elongate, conical processes. Sterna of anterior 

 segments narrow, without lobes or processes. Gonopod aperture 

 small, narrowly ellipsoid, the posterior edge elevated into a high, 

 sharp rim. Stigmata of segment 7 large and oval, located in a 

 prominent deep depression in front of the coxae. 



Gonopods relatively small, the coxae small and depressed, with 

 2 setae on the dorsal side. Solenite large, heavy at the base. Telop- 

 odite set on coxa at a right angle, the prefemur long (about 70% of 

 the telopodite length) and setose, with a long, slender, acicular 

 prefemoral process. Distal end of telopodite thin, flat, spatulate, 

 terminally acute, the entire gonopod similar to that of Boraria media. 



Female (Highlands, N.C.) : Total length 37.5 mm., width 7.2 mm., 

 W/L ratio 19.2%. Structurally similar to male with the following 

 exceptions : 



Body proportions about the same, but dorsum appearing more 

 vaulted owing to the much smaller and more depressed paranota, the 

 outer surface of which is nearly vertical on midbody segments. 

 Antennae short (5.7 mm.) and slender, reaching back only to middle 

 of paranota of 3rd segment. Sterna proportionately broader than 

 in male (1.5 mm. at midbody), coxal and prefemoral spines larger 

 and more acute; legs smaller and more slender than in male. 3rd 

 segment not modified ventrally, the sympleurites forming a narrow, 

 simple, transverse strip behind the 2nd pair of legs. Cyphopods 

 very similar to those of Boraria media. 



Variation. — Within the small range of this species there is little 

 in the natm"e of geographic variation. There is, however, pronounced 

 indi\adual and sexual variability in size, as indicated by the following 

 table (averages in parentheses) : 



sex number length {mm.) width {mm.) W/L ratio (%) 



males 6 21-30 (26) 4.1-5.8 (5.1) 19.0-20.0 (19.4) 



females 8 31-37 (35) 5.5-7.3 (6.6) 18.0-19.5 (18.8) 



In the 14 specimens measured, there was no overlap at all between 

 the total lengths for males and females, the average length being 10 

 mm. greater in females. There was virtually no overlap in width 

 values for the two sexes; here the females averaged 1.5 mm. wider 

 than males. There can be no doubt that sexual dimorphism in overall 

 size is far greater than in the other species of Boraria, and, in fact, 

 than in any other xystodesmid known to me. 



The females tend to be about the same size in both of the two areas 

 where this species has been found (the Great Smoky Mountains and 

 the vicinity of Highlands, N.C: 2 specimens from Highlands average 

 6.9 mm. in width, 6 from the Smokies average 6.6 mm.) ; however, 

 there is apparently a striking divergence between males from these 



