The Chonaphini 181 



distended mediad but not subtending distinct cavity, with numerous 

 long hairs. Receptacle large, alate, nearly completely enveloping valves, 

 extending halfway up anterior and caudal valvular surfaces, with long 

 hairs arising from ventral margin primarily from medial side. Operculum, 

 moderate-size, closely appressed to lateral side of valves. 



Variation — The prefemoral process is noticeably shorter in the 

 male from El Dorado County and rises to a peak in the midline rather 

 than on the outer or lateral margin. The acropodite therefore terminates 

 well above the latter in these individuals, and the distal bend is more 

 gradual, thereby imparting a somewhat sigmoid pattern to the distal 

 curvature rather than sinuate. The sinuate condition is noticeably dimin- 

 ished in males from west of Burney, Shasta County, and Richardson 

 Grove, Humboldt County (Figs. 56-57). 



Ecology — The specimens that I collected in El Dorado County 

 were encountered under wet hardwood litter beside a stream in a cove 

 along California highway 49. Those from Shasta County were found 

 under deciduous litter, mostly poison oak, on a bank above the Sacra- 

 mento River. The male from Butte County was found under a pine log 

 in a pine/fir association near a creek. According to Buckett and Gardner 

 (1968), S. sinuata, cited as Hybaphe sp., occurs in association with 

 luxuriant vegetation near the bottom of the south wall of the American 

 River Canyon, Placer County, and is thus ecologically segregated 

 from Wamokia discordis Buckett and Gardner, which occurs high on 

 the canyon wall, where the slope is steeper, the soil leached, and the 

 vegetation thin. 



Distribution — The northern periphery of the Sacramento Valley 

 in Shasta County to the Pacific Ocean in Humboldt County and the 

 foothills of the Sierra Nevada Mountains in El Dorado County, a 

 distance of about 147 mi (236 km) north/south and 154 mi (246 km) 

 east/west. Specimens were examined as follows: 



CALIFORNIA: Shasta Co., W of Burney, Moose Camp. Hatchet 

 Cr., M, 3F, 14 May 1966, A. A. Grigarick (UCD); along McCloud R., 

 exact location unknown, 2M, F, 4 May 1929, E. C. Van Dyke (UCD); 

 Project City N of Redding, M, 10 December 1982, B. Miller (SDMNH); 

 Redding, along Sacramento R. trail, 2M, 3F, juv., 28 April 1991, R. 

 M. Shelley (NCSM); 21 mi (33.6 km) W Redding, F, 21 December 

 1966, J. S. Buckett, M. R. Gardner (UCD); and Inwood, 4 mi (6.4 

 km) NW Shingletown, F, 20 December 1966, J. S. Buckett, M. R. 

 Gardner (UCD). Humboldt Co., Richardson Grove St. Pk., M, 15 May 

 1966, H. Wilson (UCD). Tehama Co., 2 mi (3.2 km) S Dales, off CA 

 hwy. 36, 5M, 8F, 3 juvs., 20 December 1966, J. S. Buckett, M. R. 



