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 shows affinities with A. subchalybea and A. malacothricidis. It is distinguished from both by its larger size, bluish integument, and moro deeply emarginatc apex of the labral process. From A. malacothricidis it is further I distinguished by the duller (opaque) mesoscutum and darker facial pubescence. From A. subchalybea it is also distinguished by the more closely spaced punctures on the mesoscutum and by the mixture of black and white hairs on the face of the females which gives a cloudy appearance.
FEMALE. — Integument blue-green with some golden reflections especially on metasomal terga; antenna basally and apically above dark brownish-black, terminal 8 segments yellow-brown below, forewing with stigma mahogany, clypeus with large triangular dark area with violaceous reflections covering all but narrow basolateral area; pubescence pale, white except laterally on face, apically on antennal scape, above and behind eye black, clypeus with black and white intermixed basally, tibial scopae with white anteriorly, brown posteriorly, anal fimbria gray; facial fovea with black sheen, tomentum white. Head moderately dull, closely, coarsely punctate with tessellate interspaces; clypeus with punctures contiguous; facial fovea extending from summit of eye to bottom of antennal base; eyes slightly convergent above; antenna with segments of flagellum as 14:5:5; labrum with process deeply emarginate apically (fig. 49); subgenal coronet moderately long, well developed; gena dull, moderately coarsely punctate with tessellate interspaces, longitudinally, finely striate, punctures separated by more than one diameter; pubescence of clypeus moderately long, sparse, subdepressed. Mesosoma dull, coarsely, closely punctate with granular interspaces; pronotum shallowly punctate with transversely tessellate interspaces, punctures separated by one diameter or less nearly contiguous along midline, dorsolateral angle absent without lateral fold; mesoscutum with punctures separated by one diameter or less, notaulus short, somewhat distinct; scutellum and metanotum with punctures separated by less than one diameter; propodeum rugose-punctate, enclosure basally with short, sparse, longitudinal rugulae, irregularly rugulose centrally, with rugulae becoming finer laterally, transversely tessellate apically; episternum 2 rugose-punctate; wing lightly infuscated, submarginals 1:2 (38.5:40), stigma : rest of marginal cell (16:26.5), hind wing with jugal lobe narrow, without incision between it and vannal, reaching beyond level of cu-v; posterior trochanter with long, curved, white, perfect floccus; tibial scopa long, moderately dense with hairs of posterior half branched, posterior hairs one and three-fourths times as long as width of tibia at apex; pubescence of mesoscutum moderately sparse with few long and many moderately short white hairs. Melanoma moderately shiny, moderately coarsely, moderately .sparsely punctate with granular interspaces; first tergum with punctures separated by 2 to 3 diameters; terga 2 to 4 with punctures finer, separated by 1 to 2 diameters; pubescence long, erect on basal elevation of tergum 1, short, suberect on basal elevations of terga 2 to 4, depressed apical margins of terga 1 to 3 with spatulate hairs laterally forming weak, medially interrupted hair bands, hair band complete on tergum 4. Length 8.5 to 9 mm, forewing 6.5 to 7 mm.
MALE. — Integument dark blue; antenna uniformly dark brownish-black, forewing with stigma dark brownish-black, clypeus with narrow, transverse, subapical dark band with violaceous reflections; pubescence pale, white except anal fimbria golden, laterally on face, above and behind eye black. Head dull, closely, coarsely punctate with tessellate interspaces; clypeus, latero- and supraclypeal areas with punctures contiguous; parocular depression short, linear; eyes slightly convergent below; antenna with segments 1 to 3 of flagellum as 12:5.5:7.5; labrum with process strongly recurved, deeply emarginate apically with teeth divergent (fig. 50); mandibles short; gena moderately shiny, moderately coarsely punctate with tessellate interspaces, longitudinally, finely striate, punctures separated by one diameter or slightly more; pubescence of clypeus moderately long, dense, suberect. Mesosoma dull, coarsely, closely, shallowly punctate with granular interspaces; pronotum with punctures separated by one diameter or less, transversely (("relate interspaces, dorsolateral angle absent, without lateral fold; mesoscutum with punctures separated by one diameter, notaulus short, more or less distinct; scutellum with punctures separated by less than one diameter; metanotum rugose-punctate; propodeum rugose-punctate, punctures separated by one diameter, enclosure basally with short, sparse, longitudinal rugulae, irregularly rugulose centrally with an indication of median longitudinal carinula, rugulae becoming finer laterally and apically; episternum 2 rugose-punctate; wing lightly infuscated, submarginals 1:2 (34:34), stigma : rest of marginal cell (16:23.5), hind wing with jugal lobe narrow, without incision between it and vannal, reaching level of cu-v; pubescence long, sparse. Metasoma moderately shiny, moderately coarsely, sparsely punctate with granular-scaly interspaces; punctures of terga 1 to 5 separated by 1 to 2 diameters; pubescence of tergum 1 long, erect, tergum 2 moderately long, erect, terga 3 to 5 moderately short, suberect; apicolateral hairs spatulate, forming weakly defined, medially interrupted hair bands on terga 1 to 5. Length 7 to 8 mm, forewing 6 to 6.5 mm.