Key to the species of the Cybaeus adenes group

(males of C. pearcei and C. torosus unknown; females of C. adenes and C. grizzlyi are apparently morphologically indistinguishable)

1. Males............................................................................................. 2

- Females........................................................................................... 8

2(1). Proximal arm of tegular apophysis with single, pointed tip (Figs 12, 18, 25, 56, 61, 63); with (Figs 25, 61–64) or without (Figs 12, 56) basal, pointed projection or proximally directed dorsal keel............................................ 3

- Proximal arm of tegular apophysis with tip bifid (Figs 1, 44, 50, 59–60, 65, 67) or trifid (Figs 35, 57); proximally directed dorsal keel present (but may be inconspicuous) (Figs 57, 59–60, 65, 67)......................................... 5

3(2). Patellar apophysis with 40–50 peg setae covering dorsal surface (Fig. 13). Proximal arm of tegular apophysis without basal, pointed projection or dorsal keel (Fig. 56). West central California: southern San Francisco Bay area to northern Monterey County (Fig. 69)................................................................. amicus Chamberlin & Ivie

- Patellar apophysis with about 25–30 peg setae dorsally or anterodorsally (Figs 19, 26). Proximal arm of tegular apophysis with basal, pointed projection or dorsal keel (Figs 61–64). West or east central California (Fig. 70)................... 4

4(3). Proximal arm of tegular apophysis with simple untwisted tip and prominent, bluntly pointed dorsal keel (Figs 61–62). West central California: Contra Costa and Alameda Counties (Fig. 70)................................. grizzlyi Schenkel

- Proximal arm of tegular apophysis with simple, slightly corkscrewed tip and dorsal keel a broad, bluntly pointed process dorsal to tip (Figs 63–64). East central California: Placer and El Dorado Counties (Fig. 70)..... auburn Bennett spec. nov.

5(2). Patellar apophysis nearly lacking peg setae (Fig. 36); proximal arm of tegular apophysis with broad, trifid tip and prominent dorsal keel (Figs 57–58). West central California: Santa Clara County to Monterey County (Fig. 70)............................................................................................... reducens Chamberlin & Ivie

- Ten to 30 peg setae (Figs 2, 51); proximal arm of tegular apophysis with narrower, bifid tip (Figs 59–60, 65, 67), dorsal keel reduced (Figs 59–60) or prominent (Figs 65–68). West central California: north of Santa Clara County (Figs 69–70)..... 6

6(5). Proximal arm of tegular apophysis with divergent tips (Figs 59–60). West central California: Sonoma to San Francisco Counties (Fig. 69).................................................................... adenes Chamberlin & Ivie

- Proximal arm of tegular apophysis with convergent tips (Figs 65, 67). West central California: San Mateo and Napa Counties (Fig. 70)........................................................................................... 7

7(6). Tips of proximal arm of tegular apophysis larger, relatively strongly convergent, pincer-like (Fig. 67); 13 peg setae anterodorsally on patellar apophysis (Fig. 45). West central California: San Mateo County (Fig. 70)............. sanbruno Bennett

- Tips of proximal arm of tegular apophysis relatively weakly convergent, not pincer-like (Fig. 65); about ten peg setae dorsally on patellar apophysis (Fig. 51). West central California: Napa County (Fig. 70)............. schusteri Bennett spec. nov.

8(1). Atrium with lateral margins strongly curved antero-medially (Figs 47–48); copulatory ducts contiguous (or nearly so) (Figs 48–49). West central California: San Mateo County (Fig. 70).................................... sanbruno Bennett

- Atrium with lateral margins simple, not curved anteriorly (Figs 4, 9, 15, 21, 30, 41); copulatory ducts widely separated (Figs 6, 11, 17, 24, 29, 43). East or west central California (Figs 69–71)............................................. 9

9(8). Atrium weakly to moderately concave and broad, length from epigastric groove to anterior margin <width between lateral margins (Figs 38, 41, 21–22).......................................................................... 10

- Atrium strongly concave and narrower, length 1.2–3.0 times> width (Figs 6, 15, 33, 54).......................... 11

10(9). Atrium at anterior margin of vulva (Figs 38, 41); vulva compact, apparently strongly reduced (Figs 39–40, 42–43). West central California: Santa Clara County to Monterey County (Fig. 70)..................... reducens Chamberlin & Ivie

- Atrium antero-medially located (Figs 21–22); vulva “normal” (Figs 22–24). East central California: Placer and El Dorado Counties (Fig. 70)............................................................... auburn Bennett spec. nov.

11(9). Atrium inverted U-shaped or lyriform, widest anteriorly (Figs 4, 7, 9, 30); copulatory ducts smoothly curved posteriorly, not turning anteriorly at spermathecal heads (Figs 6, 8, 28–29).................................................. 12

- Atrium inverted U- or vase-shaped (not lyriform), widest posteriorly (Figs 15, 53–54); copulatory ducts smoothly curved posteriorly (Figs 16–17) or turning anteriorly at spermathecal heads (Figs 34, 55)................................ 13

12(11). California: north and west San Francisco Bay area (Fig. 69).............................. adenes Chamberlin & Ivie

- California: east San Francisco Bay area (Fig. 70).............................................. grizzlyi Schenkel

13(11). Atrium inverted vase-shaped, lateral margins convex (Fig. 53). California: Napa County (Fig. 70)................................................................................................. schusteri Bennett spec. nov.

- Atrium inverted U-shaped, lateral margins concave (Figs 15, 33–34, 54). California: San Francisco Bay area counties south of San Francisco and Berkeley to Monterey County (Figs 69–71)............................................. 14

14(13). Copulatory ducts turning anteriorly at spermathecal heads (Figs 34, 55); length of atrium (from epigastric groove to anterior margin) 2–3 times> width (Fig. 33, 54). West central California: Alameda County (Fig. 71)........................ 15

- Copulatory ducts smoothly curved posteriorly, not turning anteriorly (Figs 16–17); length of atrium 1.2–1.6 times> width (Fig. 15). West central California: southern San Francisco Bay area to northern Monterey County (Fig. 69)............................................................................................ amicus Chamberlin & Ivie

15(14). Copulatory ducts broad anteriorly (extending laterally beyond spermathecal bases), heavily sclerotized posteriorly (Fig. 55); lateral margins clearly visible ventrally through integument of uncleared epigynum (Fig. 54).... torosus Bennett spec. nov.

- Copulatory ducts narrow anteriorly (not extending laterally beyond spermathecal bases), not heavily sclerotized posteriorly (Fig. 34); not clearly visible through epigynal integument (Fig. 33)........................ pearcei Bennett spec. nov.