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. chalybioides from which it is distinguished by its more coarsely sculptured propodeal enclosure, darker colored anal fimbria, and lower and less sharply defined dorsolateral angles of the pronotum. These two taxa are allopatric and may later be found to be distinct only at the subspecies level.
FEMALE. — Integument dark blue with some greenish reflections on metasoma; antenna dark brownish-black basally and above apically, yellow-brown below on apical 7 flagellar segments, forewing with stigma yellow-brown, clypeus with transverse, subapical dark band with violaceous reflections; pubescence dark grayish-black except mesoscutum with golden-white and black inter-mixed, metanotum and metasomal terga 1 and 2 golden-white, outer surface of tibial scopa brownish-white anteriorly, grayish-black posteriorly; facial fovea with sheen black, tomentum dark brown. Head moderately shiny, tessellate, densely, coarsely punctate; 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 deeply emarginate with lateral projections polished and elevated (fig. 23); subgenal coronet long, well developed; gena finely tessellate-punctate above, punctures becoming coarser below, punctures separated by 1 to 3 diameters; pubescence of clypeus moderately long, sparse, suberect. Mesosoma finely, moderately closely punctate with dull tessellate-granular interspaces; pronotum tessellate, finely punctate, dorsolateral angle right-angled, not elevated, not produced anteriorly, with moderately distinct lateral fold; mesoscutum with punctures fine and moderately shallow, moderately close, separated by 1 to 2 diameters, interspaces dull, granular, notaulus indistinct; scutellum with punctures moderately coarse, close, deep, separated by one diameter or less; metanotum rugose-punctate with punctures nearly contiguous or occasionally confluent; propodeum rugose-punctate, enclosure longitudinally rugose basally, irregularly rugose apically; episternum 2 rugose-punctate anteriorly, tessellate, finely, sparsely punctate posteriorly; wing infuscated, submarginals 1:2 (34:39.5), stigma : rest of marginal cell (15:24), hind wing with jugal lobe narrow and without incision between it and vannal, reaching level of cu-v or slightly beyond; posterior trochanter with long, curved, gray, perfect floccus; tibial scopa long, moderately dense, hairs of posterior three-fourths of outer surface branched, those of anterior fourth simple, posterior hairs of scopa about one and three-fourths as long as width of tibia at apex; pubescence of mesoscutum centrally with long black and shorter pale hairs intermixed. Metasoma dull, finely, sparsely tessellate-punctate, punctures separated by 1 to 3 diameters, punctures moderately coarse on tergum 1; pubescence long, erect, sparse, successively shorter on succeeding segments, that of tergum 1 twice as long as that of tergum 2. Length 9 to 10 mm, forewing 7 to 7.5 mm.
MALE. — Integument bluish with greenish reflections on clypeus and basal disks of metasomal terga; antenna uniformly dark brownish-black, forewing with stigma dark brownish-black, clypeus with transverse, subapical dark band with violaceous reflections which extend upwards medially as narrow line; pubescence pale, white except parocular and upper genal hairs black, anal fimbria deep rust-brown. Head moderately shiny, tessellate, densely punctate; clypeus, latero- and supraclypeal areas with punctures separated by less than one diameter; parocular depression short, linear; eyes slightly convergent below; antenna with segments 1 to 3 of flagellum as 12:6.5:8; labrum with process bifid, projections polished and elevated (fig. 24); mandibles long, decussate; gena above finely punctate, finely, somewhat vertically striate-tessellate, punctures becoming coarser below, punctures separated by 1 to 2 diameters; pubescence of clypeus moderately dense, long, subdepressed. Mesosoma moderately closely, finely punctate with dull tessellate-granular interspaces; pronotum tessellate, finely punctate, dorsolateral angle right-angled, not elevated, not produced anteriorly, with moderately distinct lateral fold; mesoscutum with punctures fine, moderately shallow, moderately close, separated by 1 to 2 diameters, interspaces dull, granular, notaulus indistinct; scutellum with punctures coarser, separated by one diameter or less; metanotum rugose-punctate with punctures contiguous or occasionally confluent; propodeum rugose-punctate anteriorly, finely more or less longitudinally striate-tessellate posteriorly; wing lightly infuscated, submarginals 1: 2 (31: 33), stigma : rest of marginal cell (14: 23), hind wing with jugal lobe narrow and without incision between it and vannal, reaching level of cu-v or slightly beyond; pubescence of mesoscutum long, moderately dense. Metasoma with sparse, fine, shallow punctures, separated by 1 to 3 or slightly more diameters, with moderately shiny, tessellate-granular interspaces, punctures coarser on tergum 1, sparser on depressed apical margins; pubescence pale, long, erect on tergum 1, half as long, erect on tergum 2, on terga 3 to 5 half as long as on tergum 2, erect on basal elevations, suberect, on apical margins. Length 6.5 to 7 mm, forewing 6 to 6.5 mm.
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