Key to the species of California Cephennium Müller and Kunze

1 Eyes present, reduced (Fig. 4A, C-D) ......................................................... 2

– Eyes absent................................................................................................. 4

2(1) Mesosternal process straight, not divergent at apex (Fig. 2B); frons of males with medial ridge (Fig. 4B) .............. C. celsifrons Hopp & Caterino, sp. n.

– Mesosternal process divergent at apex (Fig. 2A, D-H); frons of males flat, without medial ridge.................................................................................. 3

3(2’) Single ommatidium present on each side of head (Fig. 4D); humeral angle of elytron apically pointed (Fig. 3H); body elongate, slender............................ ........................................................... C. aridum Hopp & Caterino, sp. n.

– Four ommatidia present on each side of head (Fig. 4C); humeral angle of elytron apically rounded (Fig. 3C); body robust........................................... ...................................................... C. mariposae Hopp & Caterino, sp. n.

4(1’) Humeral angle of elytron apically pointed (Fig. 3A, G-H) ......................... 5

– Humeral angle of elytron apically rounded (Fig. 3 B-F) .............................. 6

5(4) Basal elytral sutural ridge present (Fig. 1G); apex of mesosternal keel crescent-shaped (Fig. 2G) ...................... C. urbanum Hopp & Caterino, sp. n.

– Basal elytral sutural ridge absent; apex of mesosternal keel triangulate (Fig. 2A) ................................................................ C. anophthalmicum Brendel

6(2’) Scutellum with two setae (Fig. 3D, F)........................................................ 7

– Scutellum with four setae (Fig. 3E) ...... C. canestroi Hopp & Caterino, sp. n.

7(6) Body robust; moderately large, 0.988 –1.121 mm in length; mesosternal keel strongly divergent at apex, apex 2.4× as wide as widest point anteriorly (Fig. 2D); scutellar setae long, extending past posterior margin of scutellum (Fig. 3D)........................................ C. grandarboreum Hopp & Caterino, n.sp.

– Body elongate, slender; very small, 0.646 mm in length; mesosternal keel weakly divergent at apex, apex 2× as wide as widest point anteriorly (Fig. 2F); scutellar setae short, not extending past posterior margin of scutellum (Fig. 3F)....................................................... C. gilberti Hopp & Caterino, n.sp.