Reprinted with permission of the American Entomological Society from:
LaBerge, W. E. 1977. A revision of the bees of the genus Andrena of the Western Hemisphere. Part VIII. Subgenera Thysandrena, Dasyandrena, Psammandrena, Rhacandrena, Euandrena, Oxyandrena. Transactions of the American Entomological Society 103: 1-144.
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This species is represented in collections by a series of females from California, Nevada and Oregon. The males remain unrecognized or undiscovered. These females combine the characters of obscuripostica and cristata. The labral process of latifrons is short, broad and shiny, the labral crista is present but weak, and the tibial scopal hairs are dense as in obscuripostica. However, the propodeal and metasomal sculpturing of latifrons is relatively weak as in cristata, and the metasomal tergal apical pale fasciae are weak. In addition latifrons females have the unique character of the propodeal corbicular internal hairs being entirely plumose.
FEMALE. MEASUREMENTS AND RATIOS: N = 20; length, 7.5-11.0 mm width, 2.5-3.0 mm; wing length, M = 3.84 ± 0.227 mm; FL/FW, M = 0.91 ± 0.006; FOVL/FOVW, M = 2.84 ± 0.034.
INTEGUMENTAL COLOR. — As in obscuripostica but mandible tends to be mostly rufescent.
STRUCTURE. — Antennal scape length equal to about first three and three-fourths flagellar segments; flagellar segments as in obscuripostica. Eyes, malar space, mandible and galea as in obscuripostica. Maxillary palpus as in obscuripostica but segmental ratio about as 1.0:1.0:0.8:0.8:0.6:0.6. Labial palpus as in obscuripostica but ratio about as 1.0:0.6:0.6:0.6. Labrum, clypeus, supraclypeal area, vertex, genal area, face above antennal fossae and facial fovea as in obscuripostica.
Thoracic form and sculpturing as in cristata. Wing venation as in obscuripostica but vein 1st m-cu usually meets second submarginal cell beyond middle of cell; vannal lobe hind wing broad, long.
Metasomal terga, sterna and pygidial plate sculptured as in cristata.
VESTITURE. — Generally as in obscuripostica but usually paler: tergum 1 without apical pale fascia; terga 2 and 3 with apical pale fasciae weak, interrupted medially; terga 5 and 6 with hairs ochraceous (holotype) to brown with paler hairs laterally; tibial scopal hairs usually not brown posteriorly (brown in one paratype), dense as in obscuripostica; propodeal corbiculum with long internal hairs entirely plumose.