NEW XYSTODESMID MILLIPEDS — ^HOFFMAN 385 



all keels with prominant marginal ridges; keels extending caudad of 

 median posterior portion of tergites. Segments 14 to 19 with keels 

 becoming increasingly produced caudally, those of 19 Avith posterior 

 lobes equal in length to tergite at midline. All tergites comparatively 

 fiat, and very smooth (except 18 and 19, which have tiny tubercules). 

 Kepugnatorial pores lateral in position, in some instances directed 

 slightly downward. 



Anal segment triangular in dorsal aspect, as long as broad, its 

 basal width greater than distance between keels of segment 19, trun- 

 cate distally. Anal valves inflated, glabrous, with ridges and grooves 

 on cephaloventral portion of each. Preanal scale semicircular, with 

 tubercules almost obsolete. 



Bases of last pair of legs widely separated. Legs of segments 8 to 

 18 similar; sternites of posterior pair of legs with conspicuous spines, 

 coxae and trochanters unarmed, femoral spines large. Distal tarsal 

 joint longer than basal two, and as long as femur. Coxae of second 

 legs of male with cylindrical, distally triuicate processes. Sternites 

 between fourth pair of legs of males with low rounded knobs. Pre- 

 genital legs much more hirsute than postgenital limbs. 



Gonopods in situ lie parallel and directed cephalad between the 

 bases of the seventh pair of legs, with distal ends m contact or crossed 

 Telopodite composed of two elements : a small spinif orm mesial proc- 

 ess which projects distad from the inner base of the telopodite, reach- 

 ing almost as far distad as end of the lateral process. Latter a larger, 

 mesially directed spine, tapering gently distally. Basal portion sub- 

 cylindrical, with the usual lateral setiferous shoulder. 



In life, tergites blackish, this color extending onto the keels in a 

 blunt wedge, there replaced on both corners as well as lateral margin 

 by reddish pink. Extreme edges of keels colorless. Underparts of 

 body whitish gray. Head almost completely black. Antennae brown, 

 first article white. 



Type specimen.— Male holotype in the TJ. S. National Museum, No. 

 1807, collected by me on June 19, 1947. 



Type locality.— McGrav^s Gap, 3 miles northwest of Clifton Forge, 

 Alleghany County, Va. The locality is described under Nannaria 

 ericacea (q. v.). 



Hemarhs. — The occurrence of two species of Nannaria in the same 

 ecological niche at the same locality is of some interest. As might 

 be expected, this species differs from its congener {ericacea) in sev- 

 eral respects other than the fundamental one of the male gonopods. 



The following differences will separate females as well as males : 



2V. ericacea: Head brown, edged with tan along labrum, bases of last pair of 

 legs almost in contact, preanal scale broadly triangular. 



A^. simplex: Head black to margin of labrura, bases of last pair of legs widely 

 separated, preanal scale more acute. 



