190 
Psyche 
[September 
lationship of the rhiscosomidids to the striariids is even more obvious 
than before. I think that when the striariids from the Benedict and 
Malcolm collections are thoroughly studied, it might prove desirable 
to even consider the Rhiscosomididae a subfamily of the Striariidae, 
despite the numerous differences in gross body form. (3) More 
material from California is needed, as there are probably several 
additional species occurring there. (4) Rhiscosomidids have not 
been collected in the state of Washington, where they may also 
occur, though numbers of Berlese samples from suitable habitats in 
that state contained no rhiscosomidids. The southern coastal region 
of Washington needs further exploration for millipeds. 
Ecologically, there do not appear to be any really significant dif- 
ferences in the habitats of the several known species. All have been 
collected most frequently from rotted wood, from conifer duff, and 
less frequently from deciduous duff and litter. Collections where 
elevational data is available are from 1100 ft. elevation or less. 
Nearly all were taken between November and March. However, the 
holotypes of R. montereum and R. trinitarium were collected in 
June and July respectively, and the latter was taken above 3400 ft. 
elevation. It should be emphasized that this data represents negative 
evidence from many samples from suitable habitats taken by Mrs. 
Benedict at much higher elevations and at other times of the year. 
Summer and early fall samples were poor in all types of millipeds; 
perhaps we are dealing here with a fauna adapted to low to nioderate 
temperatures and high humidity, individuals of which burrow deeper 
into the soil during unfavorable seasons. 
All type material for new species described below has been de- 
posited in the Museum of Comparative Zoology, Cambridge, Massa- 
chusetts, except for the holotype of R. trinitarium , which is the 
property of the California Academy of Sciences, San Francisco, 
California. 
Family Rhiscosomididae Silvestri 
Rhiscosomididae Silvestri, 1909, Rend. R. Accad. Lincei 18: 232; 1913, Boll. 
Lab. Zool. Portici 7: 307; Shear, 1972, Bull. Mus. Comp. Zool. 144(4): 
261. 
Type Genus: Rhisoosomides Silvestri, 1909. The family is mono- 
basic. 
Diagnosis: Distinct from species of Caseyidae in having broad 
segmental paranota, from species of Urochordeumidae in having the 
collum wider than the head, and from species of Striariidae in the 
