NEW XYSTODESMID MILLIPEDS — HOFFMAN 373 



fifteenth of full width. Keels broad, continuing slope of dorsum, 

 usually slightly separated. Anterior corners of keels rounded; pos- 

 terior corners through twelfth segment forming right angles, there- 

 after becoming increasingly produced caudally. Most keels with an- 

 terior corners lobed cephalad. Dorsolateral edges of keels produced 

 into ridges, most conspicuously so on posterior segments; repugna- 

 torial pores dorsal in position, near middle of keel. 



Collum with posterior margin relatively straight in both sexes. 



Anal segment truncate distally and bearing a small terminal tuft 

 of setae, triangular in dorsal aspect, slightly longer than broad, its 

 base Avider than the distance between keels of penultimate segment. 

 Anal valves slightly inflated, glabrous, their mesial edges produced 

 into ridges, a tiny tubercule on each valve near the center of the 

 mesial margin, no other sculpturing. Preanal scale triangular, as 

 broad as long, somewhat rounded distally, with three terminal lobes 

 of which the median lobe is conspicuously larger than the other two, 

 in this respect differing from most other species. 



Bases of the last pair of legs almost in contact mesially. Sternites 

 and coxae unarmed, femora with long spines ; legs hirsute, terminat- 

 ing in heavy curved claws. Coxae of the second pair of legs of the 

 male with the usual rounded knobs, which are truncate and flat 

 distally. 



Gonopods typical of the genus in consisting of a somewhat enlarged 

 basal portion and a rounded, loosely coiled telopodite blade, which in 

 this species makes somewhat more than a complete circle and is bent 

 mesiad and then distad, as shown in the drawings. Basal spine rather 

 small and slightly curved, arising from a cephalolateral shoulder. 

 Mesial side of base with a rounded setiferous shoulder. 



In life, dorsum black with caudolateral two-thirds of keels bright 

 yellow. A central row of large crescentic reddish-orange blotches on 

 posterior margins of the tergites ; in males these blotches are usually 

 separated from the yellow keels but in females tend to be in contact — 

 in which case the demarcation between the colors is a sharp one. 

 Head light brown, margins of labrum and antennae light brown, 

 sides of head and antennal sockets yellowish. Each article of an- 

 tennae white distall3^ Sides of body a burnished yellow, legs light 

 yellow, sternites tan. Anal valves yellowish, usually with a central 

 brown mark. 



Ty'pe s'pecimens. — Holotype and female allotype in the U. S. Na- 

 tional Museum, No. 1802. Additional male and female topopara- 

 types in my personal collection. No. 6-10-17-lb. 



Type locality. — Sinkhole at entrance to Stull's Cave, on property 

 of C. R. Stull, 8 miles southwest of Lowmoor, Alleghany County, 

 Va., on County Route 608. Seven specimens were collected during 



