NEW XYSTODESMID MILLIPEDS — HOFFMAN 377 



DescHption. — Length of holotype, 41, width, 9.4 mm.; length of 

 allotype, 39, width, 9 mm. Width of body averages 23 percent of 

 length. Sides of body subparallel, segments 4 through 15 of full 

 width. Keels moderately broad, continuing slope of dorsum, usually 

 well separated. Anterior corners of keels rounded, posterior corners 

 also somewhat rounded, not as sharply angular as in other species. 

 Keels of segment 15 not produced caudally, those of 16 noticeably 

 produced. Dorsolateral edges of keels raised into ridges; repugna- 

 torial pores situated clorsally, at about middle of keel. 



Collum with both cephalolateral and caudolateral margins tapering 

 distally. 



Anal segment triangular in dorsal aspect, longer than broad, its 

 basal width approximately equal to distance bewteen keels of the 

 penultimate segment ; truncate distally, bearing a few scattered tufts 

 of setae. Anal valves slightly inflated, bearing a few scattered setae, 

 their mesial margins raised into ridges each of which bears a single 

 seta. Preanal scale triangular, somewhat longer than broad, with 

 three terminal lobes of which the median one is conspicuously larger 

 than the other two — in this respect agreeing with A. antrostomicola. 



Bases of last pair of legs very slightly separated. Sternites and 

 coxae unspined. Trochanters and femora spined. Legs terminating 

 in a strong curved claw, with many stiff bristles around its base. 

 Coxae of second pair of legs of males with the usual cylindrical knobs 

 which in this species are flattened distally almost to the extent found 

 in antrostomicola. 



Gonopods resembling those of antrostomicola in being almost cylin- 

 drical and narrowly tapering, not flattened or bladelike and in being 

 bent mesiad and distad in more than a complete circle; differing 

 from antrostomicola in the curves of the telopodite being rather angu- 

 lar with straight interspaces and in the subterminal "heel," which 

 gives the distal third of the appendage the appearance of an Oriental 

 slipper. Base of telopodite with a mesial setiferous shoulder and 

 a cephalolateral should which bears the basal spine. 



Dorsum black, with caudolateral half of keels, tip of anal segment, 

 and legs yellow. A large, reddish-orange crescentic blotch on pos- 

 teromedian margin of each tergite. Collum with distal ends of dorsal 

 surface yellow, and a dorsomedian hourglass-shaped marking of 

 orange. Front of head black, margin of labrum brown. Antennae 

 light brown, distal portions of the articles not white. Sternites pos- 

 terior to gonopods tan (except last), sides of body brownish tan, 

 anal valves brown. 



Type specimens. — Holotype and female allotype in the U. S. 

 National Museum, No. 1804. Additional male and female topopara- 

 types are in my personal collection, Nos. 6-2647-1, 7-247-lb. All 

 specimens collected by Hobbs, Wilson, and Walton. 



