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 very similar to salictaria. Andrena ishii has a stigma as large as salictaria but the first transverse cubital vein ends about three vein widths from the pterostigma. The male can be distinguished by the very unusual genitalia (figs. 70-72) and all black antennae. The female has longer apical abdominal fasciae than salictaria (but not as long as illinoiensis). The fascia on tergum three is nearly complete in the center, while in salictaria this fascia is broadly interrupted (in illinoiensis this fascia is not reduced or interrupted in the center). Andrena ishii appears to be allopatric with other species in the illinoiensis species group.
FEMALE. MEASUREMENTS AND RATIOS. — Length, 8.0 mm; width of mesothorax, 2.1 mm; wing length from tegula, 6.3 mm; facial length/width, 1.00; foveal length/width, 3.80.
INTEGUMENTAL COLOR. — Color as in illinoiensis except: integument black to dark brown; dorsum of thorax with few, slight purple reflections, other reflections absent; flagellum brown below; tibiae and basitarsi brown, distitarsi brown and orange.
STRUCTURE. — Head as in illinoiensis except: scape distinctly shorter than flagellar segments 1-5; ultimate flagellar segment nearly twice as long as wide; maxillary palpus with segments in ratio of about 1.1:1.4:1.1:1.1:1.0:1.3; labial palpus with segments in ratio of about 1.7:1.0:1.0:1.0; labrum about three times as wide as long; labral process almost one-third as wide and almost half as long as entire labrum, almost evenly rounded from side to side; clypeus slightly more than half again as broad as long; surface between ocelli smooth, with indistinct punctures, reticular shagreening; surface above fovea coarser; facial fovea nearly as wide as eye.
Mesosoma as in illinoiensis except: posterior hind tibial spur slightly longer than anterior spur; pterostigma very large, nearly twice as wide as prestigma.
Metasoma as in illinoiensis.
VESTITURE. — Hairs as in illinoiensis except: hairs with a yellowish tinge; facial fovea distinctly chocolate brown; hairs of anterior mesoscutum with fewer branches; apical abdominal fasciae interrupted medially on terga 2 and 3.
MALE. MEASUREMENTS AND RATIOS. — Length, 6.3 mm; width of mesothorax, 1.9 mm; wing length from tegula, 6.2 mm; facial length/width, 1.00; flagellar segment 1/segment 2, 1.73.
INTEGUMENTAL COLOR. — Color as in illinoiensis except: integument black to dark brown; dorsum of thorax with few slight purplish reflections; no other reflections; flagellum all black; tarsi brown.
STRUCTURE. — Head as in illinoiensis except: scape much longer than flagellar segments 1-3; segment 1 nearly twice as long as 2, much longer than 3; maxillary palpus with segments in ratio of about 1.3:1.4:1.0:1.1:1.0:1.3; labial palpus with segments in ratio of about 1.8:1.0:1.0:1.2; labral process half as long as entire labrum and one-third as wide, evenly rounded from side to side.
Mesosoma as in ishii female except: lateral area of propodeum more coarsely sculptured; hind tibia unmodified.
Metasoma as in illinoiensis except: tergum 7 with unevenly rounded apex; sternum 6 emarginate at apex, apex flexed downward laterally.
Sternum 7 slit at apex, producing two large lobes, each lobe with numerous long, branched setae (fig. 73). Sternum 8 convex, with base expanded into large, asymmetrical (in the allotype at least) plate (fig. 74); apex slightly expanded; shaft bent downward; shaft shorter than base; posterior three-fourths of sternum setose, setae mostly long and plumose, some setae reaching beyond apex. Gonocoxite bent downward at right angle at apex, apex narrowly rounded in side view; posterodorsal part of gonoforceps with very large lobe; dorsal lobes short, wide. Penis valve very large, long, bent anteriorly; apex rounded; medially extremely expanded in side view (figs. 70-72).
VESTITURE. — Hairs as in illinoiensis except apical abdominal fasciae weaker.
VARIATION. — Apart from slight variations in size and the female apical abdominal fascial length, the only variation noticed was in hair color, female tarsal color and labral process shape. A few specimens have all white hairs rather than hairs with a yellow tinge. The tarsi are usually dark as in salictaria, but two specimens have orange tarsi like nigrae and typical illinoiensis. The female labral process may be a rounded lobe or approach a triangular shape.