1973 J Shear — Rhiscosomididae 191 
body ornamentation (Fig. 4) : tiny, sharp, seta-tipped tubercles, 
rather than longitudinal ridges. Rhiscosomidids also resemble some- 
what the larger species of the genus Tingupa (Tingupidae) , but 
may be distinguished from them by the body ornamentation as well; 
tingupids are covered with short, longitudinal carinae. 
Description: Small, striarioid millipeds (Fig. 4) with 30 post- 
cephalic segments. Collum broader than head, only slightly reflexed 
ventrad laterally. Antennae clavate, short. Mentum of gnathochi- 
larium divided. Postcollum segments with strong paranota extending 
laterad, posterior lateral corners becoming strongly reflexed posteriad, 
segmental setae long, rather blunt. Surfaces of metazonites covered 
with closely set, sharply pointed tubercles bearing tiny branched 
setae. Sixth segment of males enlarged in some species. Epiproct 
trilobed. Legs normal, pregonopodal legs of males somewhat more 
crassate than postgonopodal legs. Gonopods of males (Figs. 2, 7, 
10, 18) with sternum strongly sclerotized, two prominent groups of 
coxal processes. Anterior coxal processes partially fused in some 
species to form anterior plate. Posterior coxal processes usually fur- 
nished with fimbriate, membranous, or flagelliform branches and 
areas. Telopodites irregular, lobelike. Ninth legs reduced in size, 
with blunt coxal process, flattened, granular telopodite of one seg- 
ment (Figs. 9, 14, 16). Coxae of legs 10 with glands opening on 
anterior faces. Legs 1 1 normal. Cyphopods embraced by expansions 
of sternites and coxae of second and third legs, with postgenital 
structures of uncertain origin (Fig. 3). 
Distribution: Pacific coast region of the United States from the 
Monterey Penninsula north to the Columbia River, usually at ele- 
vations below 1 100 ft. 
Genus Rhiscosomides Silvestri 
Rhiscosomides Silvestri, 1909, Rend. R. Accad. Lincei 18: 232; 1919, Bull. 
Lab. Zool. Portici 7: 308; Shear, 1972, Bull. Mus. Comp Zool. 144(4) : 261 . 
Type Species: Rhiscosomides mineri Silvestri, by monotypy. 
Description : The genus and family are coextensive, but the fol- 
lowing additional characters may be noted. Body generally dark 
brown in color, collum usually cream-white, bases of segmental setae 
marked with light spots. In species in which sixth segment of males 
is enlarged, that segment lighter in color dorsally than the others. 
General appearance is of parallel-sided polydesmiform animals, 
squared off anteriorly at collum, tapering abruptly to blunt epiproct 
from segment 25. Ocelli vary in number from 5 to 7, variable within 
species. 
