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. malacothricidis and may be distinguished from that species by the more feebly emarginate labral process, duller (more opaque) integument on the mesoscutum, and darker facial pubes¬cence.
Females of three populations [Rosamond (5 mi. N.) and Mojave, Kern County, and Rosarito Beach, Baja California] have facial pubescence which is predominantly pale centrally and lighter colored foveal areas, but they are still distinguishable from specimens of A. malacothricidis on the basis of the other characters mentioned above.
FEMALE. — Integument dark blue-green with golden reflections; antenna basally and apically above dark brownish-black, apical 7 to 8 flagellar segments below yellow-brown, forewing with stigma mahogany, clypeus with narrow, transverse, subapical, dark band with violaceous reflections; pubescence of black on head, except tufts of intermixed black and white on lower gena and white on occiput, mesosoma with black and white intermixed on dorsum, black on pleura, white anteriorly and gray-brown posteriorly on scopa, metasoma white except gray-brown on anal fimbria; facial fovea with black sheen, tomentum gray-brown. Head moderately shiny, coarsely, closely punctate with tessellate interspaces; clypeus, latero- and supraclypeal areas with punctures separated by less than 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 as 14:5:5; labrum with process short, narrow, weakly emarginate apically with distinct median groove on outer surface, teeth appearing more or less fused (fig. 45); subgenal coronet moderately long, well developed; gena dull, moderately long, well-developed; gena dull, moderately coarsely punctate with tessellate interspaces, punctures separated by one diameter or slightly more; pubescence of clypeus long, moderately sparse, suberect. Mesosoma dull, coarsely, closely, shallowly punctate with tessellate-granular interspaces; pronotum with punctures separated by 1 to 2 diameters, finer and closer (one diameter apart) medially, dorsolateral angle absent, without lateral fold (figs. 83 and 84); mesoscutum with notaulus short, more or less distinct; mesoscutum, scutellum and metanotum with punctures separated by more than one diameter, metanotum duller with more granular tessellations; propodeum finely rugose-punctate, enclosure with sparse, short, longitudinal rugulae, medially irregularly rugulose, laterally and apically granular; episternum 2 rugose-punctate; wing very lightly infuscated, submarginals 1:2 (35:38.5), stigma : rest of marginal cell (16:23), 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 three-fourths branched, posterior scopal hairs more than twice as long as width of tibia at apex; pubescence of mesoscutum sparse, with many long black and white hairs intermixed with numerous short black hairs. Metasoma moderately shiny, moderately finely, sparsely punctate with tessellate-granular interspaces; first tergum with punctures moderately coarse, 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 to 9 mm, forewing 6 to 7 mm.
MALE. — Integument blue-green; antenna uniformly dark brown-black, forewing with stigma mahogany, 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 moderately shiny, coarsely, closely punctate with tessellate interspaces; clypeus, latero- and supraclypeal areas with punctures contiguous; parocular depression elongate, linear; eyes convergent below; antenna with segments 1 to 3 of flagellum as 13:7:8.5; labrum with process strongly recurved, feebly emarginate apically, strongly longitudinally grooved on outer face, teeth appearing fused (fig. 46); mandibles short; gena moderately shiny, moderately coarsely, shallowly punctate with roughly tessellate interspaces, punctures separated by one diameter; pubescence of clypeus moderately long, moderately dense, subdepressed. Mesosoma dull, coarsely, shallowly punctate with granular interspaces; pronotum with punctures separated by 1 to 2 diameters, interspaces transversely tessellate, dorsolateral angle absent, without lateral fold; mesoscutum with notaulus short, more or less distinct; mesoscutum, scutellum, and metanotum with punctures separated by one diameter or more; propodeum rugose-punctate with punctures separated by one diameter, enclosure with short, longitudinal rugulae on basal one-fourth, coarsely granular on apical three-fourths; episternum 2 rugose-punctate; wing pale, submarginals 1: 2 (30: 34), stigma : rest of marginal cell (15: 20), hind wing with jugal lobe narrow, without incision between it and vannal, reaching beyond level of cu-v; pubescence long, sparse. Metasoma dull, moderately finely, sparsely punctate, with granular-scaly interspaces; punctures separated by 2 to 4 diameters on terga 1 to 5; sternum 8 (fig. 79); genital capsule (fig. 67); pubescence of tergum 1 long, erect, tergum 2 moderately long, suberect; apicolateral hair spatulate forming weak medially interrupted hair bands on terga 1 to 3, more or less complete on terga 4 and 5. Length 6 to 8 mm, forewing 5.5 to 6.5 mm.