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Andrena erythronii Robertson, 1891 |
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 Mitchell, Bees of the Eastern United States, Vol. I, 1960 Andrena erythronii, figure40e |
 Mitchell, Bees of the Eastern United States, Vol. I, 1960 Andrena erythronii, figure41c |
 Mitchell, Bees of the Eastern United States, Vol. I, 1960 Andrena erythronii, figure42c |
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Taken 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 (3): 191-248.
Andrena erythronii, a moderately large spring bee of eastern North America, is associated with trout lilies (Erythronium spp.). Both sexes of erythronii can be distinguished from those of barbilabris by the more distinct pronotal humeral angles and dorsoventral ridges and by the very weak terga fasciae. The female of erythronii is further marked by a labral process distinctly broader than long, the clypeus being strongly flattened and more or less shiny, and the propodeal dorsal enclosure being weakly sculptured. The male of erythronii is further marked by the sterna having weakly formed subapical fimbriae and tergum 7 without or with an extremely narrow pygidium-like area. FEMALE. Measurements and Ratios. —N=20; length, 11-13 mm; width, 3-4 mm; wing length, M=4.08±0.163; FL/FW, M=0.97±0.004; FOVL/FOVW, M=2.72±0.032, Integumental Color. — Black except as follows: mandible with apical half rufescent; flagellum below dark reddish-brown; wing membranes hyaline, veins dark brown to reddish-brown, stigma usually rufescent; terga and sterna with narrow apical hyaline areas; tibial spurs testaceous to rufescent; distitarsi rufescent. Structure. — Antennal scape length equals first three and one-half flagellar segments; flagellar segment 1 longer than segments 2 plus 3, each of which is broader than long; segments 4-10 quadrate or longer than broad. Eyes each about three and three-fourths times as long as broad, inner margins parallel to extremely slightly converging towards vertex. Mandibles, malar space and galeae as in barbilabris. Maxillary palpus with segmental ratio about as 0.9:1.0:0.8:0.8:0.8:0.8. Labial palpus with segmental ratio about as 1.0:0.5:0.5:0.7. Labral process large, broader than long, entire or weakly emarginate; labrum below process convex, dulled by fine punctures and shagreening, with weak median crista. Clypeus flattened, with round punctures separated by half to one puncture width except in broad median longitudinal impunctate area; surface shiny to moderately so, shagreened laterally and posteriorly. Supraclypeal area, face above antennal fossae and facial foveae as in barbilabris. Vertex moderately tall, above lateral ocellus equals about one ocellar diameter, dulled by fine tessellation and obscure punctures. Genal area sculptured as in barbilabris. Pronotum laterally with distinct but blunt humeral angles and weak blunt dorsoventral ridges, surface sculptured as in barbilabris. Metasoma and scutellum as in barbilabris but punctures more crowded at least anteriorly and laterally on mesoscutum. Propodeum with dorsal enclosure dull, tessellate, weakly roughened in small posteromedian area; outside of enclosure as in barbilabris. Mesepisternum as in barbilabris. Metasomal terga dull, opaque at base to weakly shiny in apical areas, tessellate, impunctate. Pygidial plate V-shaped with blunt apex (rounded when worn), with distinct raised internal triangular area. Sterna sculptured as in barbilabris, Vestiture. — Pale ochraceous to ochraceous except as follows: facial foveal tomentum usually brown; dorsum of thorax often darker ochraceous than elsewhere; terga 2-4 with weak apical pale fasciae interrupted medially on terga 2 and 3; terga 5 and 6 brown to dark brown. Clypeus with hairs suberect, largely curved forwards. Pollen-collecting hairs as in barbilabris but propodeal corbiculum complete without internal hairs; terga with basal area hairs moderately long, sparse, mostly erect. MALE. Measurements and Ratios. — N = 20; length, 9-11 mm; width, 2-3 mm; wing length, M=3.60±0.227 mm; FL/FW, M=0.96±0.005; FS1/FS2, M=2.04± 0.046. Integumental Color. — As in female except terga and sterna with broader apical-hyaline margins and sterna usually rufescent basally. Structure. — Antenna moderately long, in repose reaching scutellum; scape length and flagellar segments as in barbilabris. Eyes each about three times as long as broad, inner margins parallel or converging slightly towards vertex (especially in large specimens). Mandibles, malar space and galeae as in female. Maxillary palpus as in female. Labial palpus with segmental ratio about as 1.0:0.6:0.6:0.7. Labral process broad at base, abruptly narrowed in apical half, with distinct but shallow apical emargination, shiny; labrum apical to process punctate basally, shiny, without distinct crista. Clypeus flat, with small round punctures separated by half to one puncture width except in small impunctate apicomedian area; surface shiny, unshagreened except occasionally delicately so posteriorly. Supraclypeal area, face above antennal fossae and vertex as in female. Genal area as in barbilabris. Pronotum as in female with blunt angles and dorsoventral ridges. Mesoscutum with obscure shallow punctures, surface opaque, tessellate. Scutellum shiny to moderately shiny, punctures separated by half to two puncture widths. Propodeum and mesepisternum as in female. Metasomal terga opaque, dulled by coarse regular tessellation, punctures sparse, minute, obscure. Tergum 7 with pygidial area absent (covered by hairs) or extremely narrow. Sterna sculptured as in barbilabris. Sternum 6 with apical margin flat, gently emarginate medially. Terminalia (Figs. 26-30) as in cymatilis but sternum 7 distinctly emarginate apically and gonostylus less angulate medially in lateral view. Vestiture. — Generally white to pale ochraceous. Terga 2-5 with weak apical pale fasciae, broadly interrupted medially on terga 2 and 3. Sterna 2-5 with weak subapical fimbriae. | |
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