Reprinted with permission from the University of Nebraska State Museum from:
Ribble, D. W. 1968. Revisions of two subgenera of Andrena, Micrandrena Ashmead and Derandrena new subgenus (Hymenoptera: Apoidea). Bulletin of the University of Nebraska State Museum 8: 1-124.
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This species is one of the more Scaphandrena-like Micrandrena and is probably more closely related to lepidii than to other Micrandrena. Andrena micheneri has a narrow stigma (for Micrandrena) and the anterior suture extending from the pit at the base of the posterior pronotal lobe is distinct. The female has a wide hind tibia with short scopal hairs and widened hind and middle basitarsi. The tooth on the tarsal claws is minute and the apical abdominal fasciae are luxuriant. The male can be distinguished by the cream-colored clypeus and parocular areas, and the antennae are dull and of moderate length.
FEMALE. MEASUREMENTS AND RATIOS. — Length, 6.8 mm; width of mesothorax, 2.3 mm; wing length from tegula, 5.6 mm; facial length/width, 0.94; foveal length/width, 3.60.
INTEGUMENTAL COLOR. — Dark brown to brown except: slight golden reflections on dorsum of thorax; flagellum yellow-orange below; terga and sterna with amber apices; distitarsi light brown; color otherwise as in piperi.
STRUCTURE. — Sculpturing in general finer over entire body than in piperi. Head otherwise as in piperi except: scape reaching to one ocellar distance from middle ocellus, nearly as long as flagellar segments 1-5; flagellar segment 1 nearly as long as 2 and 3 together; ultimate segment one and one-half times as long as broad; eye about three and one-half times as long as broad in anterior view; inner eye margins nearly parallel below; malar space about six times as wide as long; maxillary palpus with segments in ratio of about 1.1:1.6:1.4:1.3:1.0:1.3; labial palpus with segments in ratio of about 2.0:1.0:1.2:1.6; labral process one-third as wide and half as long as entire labrum, rounded from side to side; genal area in lateral view slightly wider than eye; facial fovea reaching upper eye margin.
Mesosoma as in piperi except: suture extending anteriorly from pit at base of posterior pronotal lobe distinct basally; scutellar surface very shiny, shagreening absent in center; enclosure of propodeum with very even shagreening; posterior and dorsolateral areas of propodeum with shagreening as close but more uneven than on enclosure; mesepisternal surface more granular than mesoscutal; middle and hind basitarsi slightly expanded; hind tibia very broad, one-third wider than basitarsus; tarsal claws with minute tooth on inner margin; wings with pterostigma moderate in size, half again as large as prestigma; first transverse cubital vein ending several vein widths from pterostigma.
Metasoma as in piperi except pygidial plate retracted, not seen.
VESTITURE. — Hairs as in piperi except: facial fovea white; dorsum of thorax with hairs of moderate length, thorax without distinct moss-like appearance; terga 2-4 hairs (except for apical fasciae) short, mostly simple, abdomen without dusty appearance; apical fasciae interrupted on tergum 1, partly interrupted on 2, complete on 3 and 4; tibial scopal hairs short, anterior-most hairs only weakly curved posteriorly.
MALE. MEASUREMENTS AND RATIOS. — Length, 6.0 mm; width of mesothorax, 1.8 mm; wing length from tegula, 4.6 mm; facial length/width, 1.00; flagellar segment 1/segment 2, 1.00
INTEGUMENTAL COLOR. — Black to dark brown except: slight blue-black reflections on dorsum of thorax; clypeus and parocular areas cream-colored; flagellum yellow-orange below; color otherwise as in piperi.
STRUCTURE. — Sculpturing in general finer over entire body than in piperi. Head otherwise as in piperi except: flagellar segment 1 slightly longer than 2, slightly shorter than 3; middle segments as broad as long; ultimate segment one and one-half times as long as broad; maxillary palpus with segments in ratio of about 1.0:1.4:1.1:1.1:1.0:1.3; labral palpus with segments in ratio of about 2.7:1.7:1.0:2.0; labrum slightly more than three times as wide as long.
Mesosoma as in micheneri female except: scutellum sculptured same as mesoscutum; enclosure of propodeum with shagreening less even and slightly rougher than female, sculpturing like that of posterior and dorsolateral areas; basitarsus and hind tibia unmodified; tarsal claws with large tooth on inner margin.
Exposed metasoma as in piperi.
Sternum 7 very slightly emarginate at apex, producing a square process, bearing several long, branched setae; few small, simple setae on apex below process (fig. 24). Sternum 8 (fig. 25) much like piperi except basal plate a little different in outline. Gonocoxite bent slightly downward; apex expanded in dorsolateral view, dorsolateral part with many branched setae; dorsal lobes short, wide. Penis valve bent downward, apex narrowly rounded in lateral view, medially moderately expanded, with dorsal lamellae (fig. 21-23).
VESTITURE. — Hairs as in piperi.
VARIATION. — The few specimens of this species show some variation in size. The female paratype (wing length 5.0 mm) is smaller than the holotype and the allotype is smaller than the male paratypes (wing lengths, 5.2, 4.95 mm).