Reprinted with permission of the American Entomological Society from:
LaBerge, W. E. 1987. A revision of the bees of the genus Andrena of the Western Hemisphere. Part XII. Subgenera Leucandrena, Ptilandrena, Scoliandrena and Melandrena. Transactions of the American Entomological Society 112: 191-248.
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Andrena impolita, a small desert .species from California, Arizona, and Mexico, is closely related and similar to Andrena cerasifolii. The female of impolita is difficult to separate from that of cerasifolii, but can be told by the smaller tergal punctation, the dull, shagreened terga, and the lack of distinct rugulae on the corbicular surfaces of the propodeum. The male of impolita differs from that of cerasifolii by the .smaller punctures and duller surfaces of the terga and by the longer first flagellar segment as indicated below.
FEMALE. MEASUREMENTS AND RATIOS. — N = 20;length, 10-12 mm; width, 3.0-3.5 mm; wing length, M = 4.07 ± 0,164 mm; FL/FW, M = 0.96 ± 0.008; FOVL/FOVW, M = 2.70 ± 0.037.
INTEGUMENTAL COLOR. — Black except as follows: mesosoma except propodeum and metasoma with integument dark metallic blue-black, often somewhat greenish-blue; mandible with apical third to half rufescent; flagella below dark brown to black; wing membranes hyaline, colorless; veins reddish brown to dark brown; distitarsi dark rufescent; tibial spurs rufescent.
STRUCTURE. — Antennal scape length equals first three flagellar segments or slightly more; flagellar segment 2 broader than long and shorter than segments 3, segments 3-9 longer than broad. Eyes each almost four times as long as broad, inner margins parallel. Mandibles, malar space, and galeae as in cerasifolii. Maxillary palpus as in cerasifolii but segmental ratio about as 0.7:1.0:0.8:0.8:0.6:0.6. Labial palpus with segmental ratio about as 1.0:0.6:0.5:0.5. Labrum and labral process as in cerasifolii but labrum lacking small depressed area below process. Clypeus, supraclypeal area, face above antennal fossae, vertex and genal area as in cerasifolii but clypeus with median impunctate line often longer, rarely complete.
Pronotum, mesoscutum, scutellum as in cerasifolii. Propodeum as in cerasifolii but dorsal enclosure with only weak irregular rugulae near base or at most in basal half and lateral surface (corbicular surface) without rugulae. Mesepisternum as in cerasifolii.
Metasomal terga with small punctures separated by one to three puncture widths (slightly sparser in apical areas than basally). Surfaces dull to only slightly shiny, shagreened. Pygidial plate and sternal sculpturing as in cerasifolii.
VESTITURE. — Generally while except as follows: palest specimens with vertex with black hairs, mesoscutum with small posteromedian patch of dark hairs, scutellum dark brown medially, terga 5 and 6 dark brown to black, hind tibiae and tarsi reddish brown to yellow internally; darkest specimens as dark as the darkest of cerasifolii, but few dark specimens examined. Holotype female has dark hairs mixed with white on lateral surfaces of thorax and propodeum, terga 3 and 4 with apical halves with dark hairs, and scopal hairs pale brown posteriorly.
MALE. MEASUREMENTS AND RATIOS. — N = 20; length, 7.5-11.0 mm; width, 1,5-3.0 mm; wing length, M = 3.64 ± 1.58 mm; FL/FW, M = 1.00 ± 0.004; FS1/FS2, M = 1.46 ± 0.022.
INTEGUMENTAL COLOR. — Black with strong blue-black or greenish blue-black reflections as in female; clypeus occasionally metallic.
STRUCTURE. — Antennae as in cerasifolii except scape length equals first two and one-half flagellar segments and flagellar segment 1 distinctly longer than segment 2. Eyes each about three and one-half times as long as broad, inner margins parallel or converging extremely slightly towards mandibles. Mandibles, malar space and galeae as in female. Maxillary palpus with segmental ratio about as 1.0:1.0:0.7:0.7:0.7:0.8. Labial palpus with segmental ratio about as 1.0:0.6:0.6:0.6. Labral process, labrum, clypeus, supraclypeal area, face above antennal fossae, vertex, and genal areas as in cerasifolii.
Thoracic form and sculpturing as in cerasifolii but pronotum laterally often without longitudinal rugulae in front of posterior pronotal lobe or these extremely weakly developed. Metasomal punctures small and weak as in female with terga more or less dulled by shagreening. Sternum 6 flat, apical margin gently emarginate. Penis valves as in cerasifolii; gonostylus enlarged below tip; dorsal lobe gonocoxite greatly expanded laterally and much flattened. Sternum 7 bidentate. Sternum 8 emarginate apically with lateral teeth expanded laterally (Figs. 61-65).
VESTITURE. — Generally as in female but pale hairs occasionally ochraceous rather than white; dark specimens rare; tergal hairs usually entirely pale in color.
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