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 most closely related to A. blennospermatis and more distantly to A. puthua. It is distinguished from A. puthua by the triangular non-emarginate apex of the labral process in the female and by the expanded and flattened third antennal segment in the males. From A. blennospermatis it is distinguished by its smaller size and by the narrow apex of the labral process in the females and by the non-recurved apex of the metasoma and the narrower apex of the last visible sternum in the males.
The only apparent variation is in the average size of individuals in different populations, but this character does not appear to follow any directional trends.
FEMALE. — Integument golden olive-green; antenna basally and dorsally dark brown with mahogany reflections, antenna below yellow-brown on apical seven segments, forewing with stigma dark brown with mahogany reflections, apical depressed margins of metasomal terga occasionally with brownish reflections, clypeus with moderately large, subapical, triangular dark area with violaceous reflections; pubescence pale, white except on frons and antennal scape long golden, on mesoscutum long golden intermixed with short white hairs, on anal fimbria golden-brown, on base of tibial scopa dark brownish grading to golden-brown apically along posterior edge of tibia; facial fovea with black sheen, tomentum white. Head moderately shiny, moderately finely, sparsely punctate with tessellate interspaces, clypeus, latero- and supraclypeal areas with punctures separated by 2 diameters; facial fovea extending from summit of eye to middle of antennal base; eye slightly arcuate medially; antenna with segments 1 to 3 of flagellum as 10.5: 3: 3.5; labrum with process triangular with a short tumid apical process (fig. 17); subgenal coronet moderately long, well developed; gena moderately shiny, moderately coarsely punctate with tessellate interspaces, punctures separated by 1 to 2 diameters dorsally, becoming more sparsely and more coarsely punctate posteroventrally; pubescence of clypeus moderately long, sparse, subdepressed. Mesosoma moderately dull, moderately coarsely punctate with tessellate-granular interspaces; pronotum shinier, with punctures separated by 1 to 2 diameters, dorsolateral angle right-angled with distinct lateral fold, posterior margin of pronotum transverse; mesoscutum with notaulus distinct; mesoscutum, scutellum, metanotum with punctures separated by 1 to I diameters; propodeum punctate-tessellate, coarsely granular, punctures separated by 1 to 2 diameters, enclosure with few, very fine, short rugulae along basal margin, otherwise shiny, tessellate; episternum 2 moderately coarsely punctate with tessellate interspaces, punctures separate by one diameter, posteriorly tessellate with finer, sparser punctures; wing lightly infuscate submarginals 1: 2 (29: 26); stigma : rest of marginal cell (26: 34); hind wing with jugal lobe moderately broad and with incision between it and vannal, reaching beyond level of cu-v posterior trochanter with moderately long, moderately curved, white, imperfect floccus, hairs short, straight basally, increasing in length and curvature apically; tibial scopa with dense short, finely branched hairs, posterior scopal hairs subequal in length to width of tibia at apex; pubescence of mesoscutum with many dense, moderately short, white hairs and few long, golden-brown hairs interspersed. Metasoma shiny, finely, sparsely punctate with tessellate interspaces, punctures of basal elevations of terga 1 to 4 separated by 2 diameters, becoming closer on depressed apical margins; pubescence short, subdepressed on basal elevations, longer, spatulate, and depressed, forming hair bands on apical depressed margins, decreasingly medially interrupted from tergum 1 to 3, complete on tergum 4. Length 6.5 to 7 mm, forewing 5 to 5.5 mm.
MALE. — Integument dark blue-green; antennal scape, pedicel, and first flagellar segment dark brownish-black, rest of antennal flagellum above mahogany, below yellow-brown, forewing with stigma and basal half of depressed apical margins of metasomal terga brown, apex of metasomal terga translucent, clypeus with narrow, transverse, subapical dark band with violaceous reflections; pubescence pale, white except on mandible and labrum golden. Head moderately shiny, moderately finely, densely punctate with tessellate interspaces; clypeus, latero- and supraclypeal areas with punctures separated by one diameter; parocular depression short, tear-shaped; eyes convergent below; antenna with segments 1 to 3 of flagellum as 10.5: 4: 5; first flagellar segment flattened and widened, width: length (7: 10.5); labrum with process short, broad, shallowly emarginate apically (fig. 18); mandibles moderately long, decussate; gena dorsally moderately shiny, moderately coarsely punctate with tessellate interspaces, punctures separated by 1 to 2 diameters, ventroposteriorly shinier with punctures sparser; pubescence of clypeus long, dense, subdepressed. Mesosoma dull, moderately coarsely, shallowly punctate with tessellate-granular interspaces; pronotum with punctures separated by 1 to 2 diameters, tessellations transverse, dorsolateral angle right-angled with distinct lateral fold, posterior margin of pronotum transverse; mesoscutum with notaulus distinct; mesoscutum, scutellum, metanotum with punctures separated by two diameters, becoming finer and deeper on scutellum and metanotum; propodeum dull, moderately coarsely punctate with tessellate interspaces, punctures separated by 1 to 2 diameters, enclosure with few fine, short rugulae basally, otherwise tessellate; episternum 2 moderately coarsely punctate with roughened tessellate interspaces, punctures separated by one diameter; wing pale, submarginals 1: 2 (26: 22.5), stigma : rest of marginal cell (12: 15); hind wing with jugal lobe broad and with incision between it and vannal, reaching beyond level of cu-v; pubescence moderately long, moderately sparse. Metasoma cordate, moderately shiny, finely punctate, with tessellate interspaces; first tergum with punctures shallow, moderately coarse, and separated by 2 diameters, punctures finer on apical depressed margin, interspaces granular; terga 2 to 5 with fine, deep punctures, separated by 2 diameters, interspaces finely transversely tessellate; tergum 7 with narrow, longitudinal, median elevation; sternum 8 (fig. 74); genital capsule (fig. 62); pubescence moderately long, suberect on basal elevation of tergum 1, moderately short, subdepressed on basal elevation of terga 2 to 5, moderately long, subdepressed on depressed apical margin of tergum 5, spatulate hairs on depressed apical margins of terga 1 to 4 forming hair bands, medially interrupted on anterior segments, nearly complete on tergum 4. Length 6 to 6.5 mm, forewing 4.5 to 5 mm.