Reprinted with permission of the American Entomological Society from:
LaBerge, W. E. 1989. A revision of the bees of the genus Andrena of the Western Hemisphere. Part XIII. Subgenera Simandrena and Taeniandrena. Transactions of the American Entomological Society 115: 1-56.
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Andrena pensilis is a California species that is readily recognized in the female sex by the long, relative simple, tapering clypeal hairs, which are wavy distally, The males of pensilis can be readily separated from the preceding species by the long first flagellar segment and by the dense clypeal beard obscuring the surface, which is shiny at least near apical margin. The females have cuneate hind tibiae with short scopal hairs as in nasonii.
FEMALE. MEASUREMENTS AND RATIOS. — N = 20; length, 8-10 mm; width, 2.5-3.0 mm; wing length, M = 3.30 ± 0.047 mm; FL/ FW, M = 0.99 ± 0.006; FOVL/FOVW, M = 3.05 ± 0.047.
INTEGUMENTAL COLOR. — Black except as follows: mandible with apical third or more rufescent; wing membranes hyaline, moderately infumate, yellow, veins dark reddish brown to brown; metasomal tergal apices narrowly hyaline; distitarsi dark brown; tibial spurs testaceous; pygidial plate often rufescent medially.
STRUCTURE. — Antennal scape as long as first three and one-half flagellar segments; flagellar segment 1 distinctly shorter than segments 2 and 3 together; segment 2 about equal in length to segment 3 and shorter than segment 4; segment 4 quadrate, succeeding segments longer than broad. Eyes each four times as long as wide or slightly longer, inner margins parallel or converging slightly towards mandibles. Mandibles and galeae as in nasonii. Maxillary palpus as in nasonii but segmental ratio about as 1.0:0.8:0.8:0.8:0.4:0.7. Labial palpus as in nasonii but segmental ratio about as 1.0:0.5:0.4:0.5. Labral process with apical margin rounded, surface shiny; labrum without cristae. Clypeus flattened, punctures small but distinct, surface weakly shagreened in posterior half or more, shiny at least apically. Supraclypeal area dulled by minute punctures and dense shagreening. Face above antennal fossae as in nasonii. Vertex above lateral ocellus equals about one ocellar diameter, opaque. genal area as in nasonii.
Pronotum as in nasonii. Thoracic sculpturing as in nasonii except as follows: mesoscutal punctures barely visible; scutellum often moderately shiny; propodeal dorsal enclosure often without rugulae except at extreme base, dorsolateral and posterior surface punctures distinct but obscured by tessellation. Fore wing with vein r usually longer, 3 to 4 vein widths in length, rarely less.
Metasomal 1 tergum with small distinct punctures separated mostly by half a puncture width or slightly more, somewhat obscured by reticular shagreening, apical area densely punctate, often moderately shiny. Terga 2-4 similar but punctures slightly sparser, more obscured by shagreening, narrow apical rims shiny. Pygidial plate as in angustitarsata. Sterna sculptured as in nasonii.
VESTITURE. — White to pale ochraceous except as follows: clypeal hairs reddish brown to dark brown; facial fovea with posterior third to half with brown hairs, white apically; terga 5 and 6 with hairs white to ochraceous, terga 3 and 4 with basal area hairs pale; terga 2-4 with narrow apical white fasciae but broadly interrupted medially on tergum 2, complete on terga 3 and 4; hind tibial scopal hairs white, occasionally brown near pygidial plate. Clypeus with hairs almost simple, long and directed downwards (towards labrum), tapering and extremely slender and wavy in outer half.
MALE. MEASUREMENTS AND RATIOS. — N = 20; length, 7-9 mm; width, 1.5-2.0 mm; wing length, M = 2.85 ± 0.113 mm; FL/FW, M = 1.08 ± 0.014; FS1/FS2, M = 1.80 ± 0.033.
INTEGUMENTAL COLOR. — As in female except as follows: flagellar segments brown below; wing membranes hyaline, not at all infumate; metasomal terga with apical areas often yellowish brown, more broadly hyaline apically than in female.
STRUCTURE. — Antennae short, in repose barely reaching scutellum; scape as long as first two and one-half flagellar segments or almost so; flagellar segment 1 slightly shorter than segments 2 and 3 together; segment 2 shorter than segment 3 which is quadrate and shorter than segment 4; median flagellar segments slightly longer than broad. Malar space, galea and labrum as in female. Maxillary palpus as in female but segmental ratio about as 1.0:0.8:0.8:0.8:0.7:0.7. Labial palpus as in female but segmental ratio about as 1.0:0.4:0.3:0.4. Clypeus flattened, with small punctures separated mostly by one or more puncture widths, surface dulled in posterior half or more by fine shagreening, shiny apically. Supraclypeal area, face above antennal fossae, vertex and genal area as in female.
Thoracic form and sculpturing as in female but mesoscutal punctures sparser, separated by two to three puncture widths. Metasomal tergum 1 with basal area with minute obscure punctures separated by two or more puncture widths, surface shagreened, dull; apical area shiny to moderately shiny, punctate at least at base. Terga 2-5 similar but basally area punctures denser, less distinct than in tergum 1. Sterna as in nasonii. Terminalia as in Figures 22-26.
VESTITURE. — White to extremely pale ochraceous. Metasomal terga 2-5 without apical pale fasciae or these extremely weak and usually reduced to short lateral fringes. Sterna without subapical fimbriae.