Reprinted with permission from the University of Nebraska State Museum from:
Ribble, D. W. 1968. Revisions of two subgenera of Andrena, Micrandrena Ashmead and Derandrena new subgenus (Hymenoptera: Apoidea). Bulletin of the University of Nebraska State Museum 8: 1-124.
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The female of californiensis is easily distinguished by the long plumose hairs in the center and along the anterior margin of the propodeal corbicula. Andrena ziziaeformis exhibits this character but it has an entirely different range (eastern U. S.) and unlike californiensis has a widened tibia with short scopal hairs. The male has a long process on the gena below the mandible which is lacking in ziziaeformis. In the male of californiensis the suture extending across the base of the posterior pronotal lobe ends below the humeral angle, the base of the clypeus is very weakly shagreened, and there are only a few chocolate brown hairs which are restricted to the thorax. Both sexes have a short clypeus.
FEMALE. MEASUREMENTS AND RATIOS. — Length, 7.2 mm; width of mesothorax, 2.0 mm; wing length from tegula, 5.3 mm; facial length/width, 0.94; foveal length/width, 3.00.
INTEGUMENTAL COLOR. — Color as in vandykei except flagellum yellow-orange below.
STRUCTURE. — Head as in vandykei except: scape reaching to within one ocellar distance from middle ocellus; flagellar segment 1 slightly shorter than 2 and 3 together; segment 3 not tapered; middle segments slightly longer than wide; ultimate segment one and one-half times as long as broad; malar space about five times as wide as long; mandible less sharply pointed than in vandykei; maxillary palpus with segments in ratio of about 1.3:1.3:1.0:1.4:1.1:1.3; labial palpus with segments in ratio of about 1.8:1.2:1.0:1.6, segment 4 distinctly flattened; labrum half as long as wide; genal area in side view as wide as eye; facial fovea not extending above eye, dorsally nearly as wide as eye.
Mesosoma as in vandykei except: pronotum with suture at base of posterior pronotal lobe reduced to an oblong pit, humeral angle strong, abruptly elevated above dorsal surface of pronotum, forming long crease extending halt way to midline; scutellum very shiny in center, shagreening absent; propodeum with shagreening not becoming granular towards base of enclosure; wings with pterostigma large, half again as wide as prestigma; first transverse cubital vein ending three vein widths from pterostigma.
Metasoma as in vandykei.
VESTITURE. — Hairs as in vandykei except: hairs along fovea white; leg hairs mostly white, amber hairs on apex of fore tibia, fore tarsus, apex of hind femur and base of hind tibia; hairs on dorsum of thorax short, with many branches, giving thorax a moss-like appearance; anterior margin and interior of propodeal corbicula with long plumose hairs; apical abdominal fasciae present on terga 1-4, reduced to a few hairs laterally on tergum 1, partly interrupted in center of tergum 2, complete on 3 and 4.
MALE. MEASUREMENTS AND RATIOS. — Length, 5.5 mm; width of mesothorax, 1.3 mm; wing length from tegula, 4.5 mm; facial length/width, 0.85; flagellar segment 1/segment 2, 1.00.
INTEGUMENTAL COLOR. — Color as in vandykei except: integument lighter in color, bee appearing brownish rather than blackish, only vertex of head black; flagellum pale yellow-brown below.
STRUCTURE. — Head as in vandykei except: scape slightly shorter than flagellar segments 1-3; segment 1 equal to 2 in length, much shorter than 3; middle segments almost twice as long as broad; ultimate segment more than twice as long as broad; eye about three and one-half times as long as broad in anterior view; maxillary palpus with segments in ratio of about 1.3:1.3:1.1:1.2:1.0:1.3; labial palpus with segments in ratio of about 1.7:1.1:1.0:1.1; clypeus protruding beyond lower margin of eye half width of eye in lateral view, entire clypeus with very weak reticular shagreening; genal area in lateral view one-third wider than eye.
Mesosoma as in vandykei except pronotum with suture extending vertically from leg base ending below humeral angle.
Metasoma as in vandykei except sternum 6 with apical margin emarginate, flexed downward medially.
Terminalia (figs. 100-104) very similar to arctostaphylae except: gonocoxite narrower; apex of gonoforceps more expanded along inner margin in ventral view, base of gonoforceps narrower in lateral view.
VESTITURE. — Hairs as in vandykei except nearly all white, few chocolate brown hairs on dorsum of thorax posteriorly.
VARIATION. — The two females from Lakeport (Lake County) are most different from the allotype (from Los Angeles County). They differ in several respects: smaller overall size, head more rounded, clypeus more heavily shagreened, crease below humeral angle less well developed, apical abdominal fasciae less well developed. These differences are slight and a few of the specimens from central coastal California are intermediate between the Lakeport and typical specimens. The characters mentioned just above occur in various combinations and show intermediate states. For these reasons the Lakeport specimens are considered californiensis. Sufficient material is not available to determine the extent of north-south geographic variation, but available material indicates that variation is slight. The lack of males from north of northeastern Ventura County hampers an understanding of the variation in this species. Two other variations were noticed. The galea sometimes has the surface very weakly shagreened. Males are often darker in color than the male holotype.
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