Reprinted by permission of the Regents of the University of California from:
Thorp, R. W. 1969. Systematics and ecology of bees of the subgenus Diandrena (Hymenoptera: Andrenidae). University of California Publications in Entomology 52: 1-146.
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This species is related to Andrena submoesta and A. blennospermatis and is distinguished from them by the deeply emarginate apex of the labral process in the females and the conical (not flattened) third antennal segment in the males.
Some population variation exists in the color of the basal elevations of the metasomal terga of the males. In males from populations in northern California and Baja California the tergal bases are predominantly dark greenish metallic, while in males from populations in Riverside and Los Angeles counties of California they are predominantly brownish and "shellacked" in appearance, with only faint indications of metallic greenish color.
FEMALE. — Integument gray-green; antenna basally and above apically dark brownish-black yellowish-brown below on apical seven segments, forewing with stigma yellowish-brown clypeus with largo subapical dark triangle with violaceous reflections; pubescence pale, white; facial fovea with sheen gray-white, tomentum white. Head moderately shiny, moderately coarsely, shallowly punctate with tessellate interspaces; clypeus, latero- and supraclypeal areas with punctures separated by about one diameter; facial fovea extending from summit of eye to middle of antennal base; eye slightly arcuate medially; antenna with segments 1 to 3 of flagellum 9:3:3; labrum with process broader than long, deeply emarginate with apices divergent (fig. 15); subgenal coronet moderately long, well developed; gena moderately shiny, tessellate, finely punctate, punctures separated by 1 to 2 diameters, becoming shinier, more coarsely and sparsely punctate below; pubescence of clypeus moderately long, sparse, subdepressed. Mesosoma dull, moderately coarsely punctate with granular-granular interspaces; pronotum moderately shiny, finely transversely tessellate with punctures separated by 1 to 2 diameters, dorsolateral angle somewhat right-angled with more or less distinct lateral fold, posterior margin of pronotum transverse; mesoscutum with notaulus distinct; mesoscutum and scutellum with coarse tessellations (pebbled surface), punctures separated by one diameter; metanotum dull, rugose-punctate with punctures contiguous; propodeum moderately coarsely punctate with dull, tessellate inter spaces, punctures separated by slightly more than one diameter, enclosure with fine, short rugulae basally with an indication of a long, fine, median, longitudinal carinula, otherwise coarsely tessellate; episternum 2 anteriorly moderately coarsely punctate with tessellate interspaces, punctures separated by one diameter, posteriorly tessellate with fine punctures; wing lightly infuscated, submarginals 1:2 (24:22.5), stigma : rest of marginal cell (17:32.5), hind wing with jugal lobe moderately broad and with incision between it and vannal lobe, reaching beyond level of cu-v; posterior trochanter with moderately long, moderately curved, white, imperfect floccus, hairs short and straight basally increasing in length and curvature apically; tibial scopa with dense, short, finely branched hairs, posterior scopal hairs equal in length to width of tibia at apex; pubescence of mesoscutum with dense, short hairs and a few long hairs interspersed. Metasoma moderately dull, finely punctate with tessellate interspaces, punctures separated by 1 to 2 diameters, closest on depressed apical margins; terga becoming duller from 1 to 4, and punctures less distinct; pubescence short, subdepressed on basal elevations, longer, depressed, and forming hair bands on depressed apical margins, decreasingly medially interrupted from tergum 1 to 3, complete on tergum 4. Length 6.5 to 7 mm, forewing 4.5 to 5 mm.
MALE. — Integument gray-green with some bluish reflections; antennal scape pedicel and first three flagellar segments dark brownish-black; antennal flagellum apically brown; forewing with stigma yellow-brown; apical depressed margins of metasomal terga and sterna yellow-brown basally, pale translucent apically; clypeus with narrow transverse, subapical dark band with violaceous reflections; pubescence pale, white. Head moderately shiny, moderately coarsely, densely punctate with tessellate interspaces; clypeus shiny, punctures larger, separated by less than one diameter; parocular depression short, tear-shaped; eyes convergent below; antenna with segments 1 to 3 of flagellum as 9:4:4; labrum with process strongly recurved and deeply emarginate apically (fig. 16); mandibles moderately long and decussate; gena moderately shiny, tessellate, finely punctate, punctures separated by 1 to 2 diameters dorsally, becoming shinier and more sparsely punctate posteroventrally; pubescence of clypeus moderately long, dense, depressed. Mesosoma dull, moderately coarsely punctate with tessellate interspaces; pronotum moderately shiny, shallowly punctate with transversely tessellate interspaces, punctures separated by bout two diameters, dorsolateral angle right-angled with moderately distinct lateral fold, posterior margin of pronotum transverse; mesoscutum with notaulus distinct; mesoscutum and scutellum dull, punctures separated by one diameter, interspaces granular; metanotum rugose-punctate, punctures contiguous; propodeum dull, tessellate, punctate with punctures separated by one diameter, enclosure with fine, short, longitudinal rugulae basally, with median long carinula, otherwise coarsely granular-tessellate; episternum 2 moderately coarsely punctate with tessellate interspaces, punctures separated by one diameter, posteriorly tessellate, finely punctate; wing lightly infuscated, submarginals 1:2 (22:24), stigma : rest of marginal cell (10:15), hind wing with jugal lobe moderately broad and with incision between it and vannal, reaching beyond level of cu-v; pubescence of moderately long, moderately dense. Metasoma cordate, moderately shiny, finely punctate with faint transverse tessellations; first tergum with punctures moderately large, separated by 1 to 2 diameters; terga 2 to 5 with punctures finer, separated by 1 to 2 diameters; pubescence short, subdepressed, hairs on depressed margin spatulate, forming weakly defined hair bands. Length 6 to 65. mm, forewing 4.5 mm.