Cybaeus pearcei Bennett spec. nov.

Figs 33–34, 71

Type material. Holotype ♀. U.S.A.: California: Alameda County, Calaveras Dam, 15 March 1939, W.M. Pearce (AMNH).

Etymology. The specific epithet is a patronym honoring W.M. Pearce, the collector of the only known specimen of this species.

Diagnosis. The female of C. pearcei is characterized by its small atrium (Figs 33–34): strongly concave and inverted U–shaped with inconspicuous relatively narrowly separated parallel lateral margins and length (from epigastric groove to anterior margin) 2.5–3.0 times width (between lateral margins). Other females of the adenes group that possess strongly concave inverted atria have the margins farther apart and not usually parallel and length to width ratios of 1.2–2.0 ( C. adenes: Figs 4, 9; C. amicus: Figs 15–16; C. grizzlyi: Fig. 30; C. sanbruno: Figs 47–48; C. schusteri: Fig. 53; C. torosus: Fig. 54). The male is unknown.

Description. Femora unbanded.

Female: (n=1). Copulatory ducts (Fig. 34) attached to anterolateral margins of atrium, nearly contiguous anteriorly; Bennett’s glands small and inconspicuous although possibly the specimen is newly matured and the glands are not fully developed (see Bennett 2006).

Holotype CL 2.00, CW 1.38, SL 1.03, SW 0.98.

Distribution. Known only from the type locality near the southern boundary of Alameda County in west central California (Fig. 71).