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. gnaphalii and is distin¬guished from that species by the shiny mesoscutum, white facial pubescence, and the finely tessellate lateral areas of the pronotum.
Andrena olivacea is the only species of the subgenus which occurs primarily in the desert areas.
FEMALE. — Integument bluish with olive-green reflections; antennae dark brownish-black basally and above apically, yellow-brown below on apical 8 to 9 flagellar segments; clypeus with large subapical dark triangle with violaceous reflections., forewing with stigma yellow-brown; pubescence pale, white except grayish-brown on vertex above eye, few dark intermixed with numerous white hairs on mesoscutum, anal fimbria gray-brown, outer face of tibial scopa white anteriorly, gray-brown posteriorly; facial fovea with sheen gray, tomentum whitish. Head moderately shiny, coarsely, closely punctate with smooth interspaces; clypeus with punctures separated by less than one diameter, latero- and supraclypeal areas with punctures contiguous and shallower; 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 15: 4: 5; labrum with process broad, deeply emarginate, apices divergent (fig. 25); subgenal coronet long, well developed; gena moderately shiny, tessellate, moderately coarsely, closely punctate above, punctures separated by 1 to 2 diameters, longitudinally finely striate-punctate posteroventrally, punctures separated by 2 diameters; pubescence of clypeus moderately long, sparse, suberect. Mesosoma moderately shiny, coarsely, closely punctate with interspaces finely, tessellate to smooth; pronotum duller, finely, sparsely punctate with transversely tessellate interspaces, dorsolateral angle right-angled with definite lateral fold, posterior margin of pronotum nearly transverse; mesoscutum with punctures separated by one diameter or less, interspaces tessellate peripherally, shinier, more finely tessellate or smooth centrally, notaulus short, moderately distinct; scutellum and metanotum with punctures separated by less than one diameter anterolaterally, nearly contiguous peripherally and along midline; propodeum rugose-punctate, enclosure with large inner triangle of moderately regularly longitudinal rugosities basally, becoming irregularly rugose apically, lateral border with rugae becoming leys distinct, apical edge transversely tessellate; episternum 2 rugose-punctate; wing lightly infuscated, submarginals 1:2 (33.5:36); stigma : rest of marginal cell (15:24), hind wing with jugal lobe narrow and without incision between it and vannal, reaching beyond level of cu-v; posterior trochanter with long, curved, white, perfect floccus; tibial scopa long, dense, with hairs of outer and posterior faces branched, long, curled hairs of anterior face simple, posterior hairs of scopa one and one-half times as long as width of tibia at apex; pubescence of mesoscutum with numerous moderately short dark and pale hairs intermixed laterally, several long dark and numerous moderately short pale hairs intermixed centrally. Metasoma moderately shiny, moderately coarsely punctate; punctures of first tergum with interior edges raised, separated by 1 to 3 diameters, interspaces tessellate; punctures of terga 2 to 4 finer, separated by one diameter or slightly more, interspaces tessellate; pubescence of tergum 1 moderately long, suberect, terga 2 to 4 short, suberect, and without apical hair bands. Length 9 to 10 mm, forewing 6.5 to 7 mm.
MALE. — Integument bluish with yellow-green reflections on face and basal elevations of metasomal terga; antenna uniformly dark brownish-black, clypeus with narrow, subapical dark band with violaceous reflections, forewing with stigma yellowish-brown; pubescence pale white except brown laterally on face and above eye, golden on anal fimbria. Head moderately shiny, densely, coarsely punctate; punctures of clypeus nearly contiguous; parocular depression short, linear, with violaceous reflections; eyes slightly convergent below; antenna with segments 1 to 3 of flagellum as 13: 5: 7; labrum with process strongly recurved and deeply emarginate apically (fig. 26); mandibles long, decussate; gena moderately shiny, tessellate with fine vertical striae, moderately coarsely punctate with punctures separated by about 2 diameters above, longitudinally striate, punctate-punctate with punctures separated by 2 diameters or more below; pubescence of clypeus moderately long, moderately dense, subdepressed. Mesosoma moderately shiny, moderately coarsely punctate with finely tessellate interspaces; pronotum finely, sparsely punctate with transversely tessellate interspaces, dorsolateral angle right-angled with distinct lateral fold, posterior edge of pronotum transverse; mesoscutum slightly duller, with punctures separated by slightly more than one diameter to less than one, notaulus short, distinct; scutellum with punctures separated by less than one diameter anterolaterally, contiguous peripherally and along midline; metanotum dull, rugose-punctate; propodeum coarsely rugose-punctate, enclosure longitudinally rugose with long median carina; episternum 2 rugose-punctate; wing pale, submarginals 1:2 (31:36), stigma : rest of marginal cell (14:24), hind wing with jugal lobe narrow and without incision between it and vannal, reaching beyond level of cu-v; pubescence long, moderately dense. Metasoma shiny, finely tessellate, moderately finely, sparsely punctate; punctures of first tergum moderately coarse, separated by 2 to 4 diameters, interspaces moderately dull, tessellate; terga 2 to 5 shinier, more finely punctate, punctures separated by 3 to 4 diameters; sternum 8 (fig. 76); genital capsule (fig. 64); pubescence long, suberect on tergum 1, about half as long, suberect on tergum 2, short, suberect on terga 3 to 5. Length 7 to 8 mm, forewing 6 to 6.5 mm.