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Andrena osmioides Cockerell, 1916
Andrena (Scoliandrena) osmioides benitonis Lanham, 1949

Life   Insecta   Hymenoptera   Apoidea   Andrenidae   Andrena
Subgenus: Scoliandrena

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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 osmioides is known only from California and can be separated from the other Scoliandrena by the bright blue-green, metallic tergal integument and the less distinctly punctate metasomal terga of both sexes. This species is rather variable in general size and in color of the vestiture, with some tendency to form microgeographical races in the terrain of California. The present author prefers not to rccognize these formally with scientific names.

FEMALE. MEASUREMENTS AND RATIOS. N = 20; length, 10-12 mm; width, 3-4 mm; wing length, M = 3.87 0.176 mm; FL/FW, M = 0.89 0.003; FOVL/FOVW, M = 2.94 0,046.

INTEGUMENTAL COLOR. Black except as follows: mandible with apical half rufescent; flagellar segments dark brown below; wing membranes hyaline, colorless to yellow, veins dark brown; tibial spurs testaceous to dark brown; metasomal terga 1-4 metallic blue-green, often with golden or violaceous reflections basally.

STRUCTURE. Antennal scape equal to or slightly longer than first three flagellar segments; flagellar segment 1 as long as following two and one-half segments; segments 2 and 3 slightly broader than long; segment 4 quadrate; segments 5-10 longer than broad. Eyes each about three and three-fourths times as long as broad, inner margins parallel. Mandibles moderately long, in most specimens badly worn but when not worn, somewhat decussate apically. Malar space short, linear. Galea small, narrow, outer-apical margin convex or straight; surface moderately shiny; provided with abundant short hooked hairs. Maxillary palpus much shorter than galea (about as 3:4 or 5); segmental ratio about as 1.0:1.0:0.5:0.3:0.5. Labial palpus much reduced in length; segmental ratio about as 1.0:0.5:0.3:0.5. Apex of prementum provided with abundant short hooked hairs; stipes almost bare of hairs, shiny; glossa short, broad, rounded. Labral process extremely large, triangular with slightly rounded and thickened tip (almost an isosceles triangle), shiny; labrum below process with margin pointed medially, with median crista and laterally with irregular longitudinal rugulae. Clypeus with small dense punctures separated by half to one puncture width; surface dulled by reticular shagreening; without median impunctate line. Supraclypeal area sculptured like clypeus but punctures shallow and obscure. Face above antennal fossae with fine longitudinal rugulae reaching ocelli; with abundant minute interrugal punctures. Vertex above lateral ocellus equals slightly less than one ocellar diameter; surface opaque, densely tessellate with scattered obscure punctures. Facial foveae broad, shallow, extending to below a line at lower margins antennal fossae; separated from lateral ocellus by about one and one-fourth ocellar diameters. Genal area in profile broader than eye; surface opaque, tessellate.

Pronotum laterally with distinct but rounded humeral angle and distinct but blunt dorsoventral ridge; surface dulled by reticular shagreening except in narrow crease anterior to pronotal lobe. Mesoscutum opaque, punctures small, crowded, shallow, obscured by dense fine tessellation. Scutellum as in mesoscutum. Propodeum with dorsal enclosure opaque, smooth, tessellate; outside of enclosure similar hill extremely shallow, sparse punctures barely visible. Mesepisternum similar to propodeum outside of enclosure but obscure shallow punctures often more abundant.

Metasomal terga 1-4 opaque, coarsely tessellate except extremely narrow shiny apical margins. Pygidial plate narrow, V-shaped with apex rounded, with internal raised triangular area absent or weak. Sterna 2-5 with basal areas with basal areas with small punctures separated mostly by one to two puncture widths, becoming sparser towards base of each; apical areas impunctate, tessellate.

VESTITURE. Variable in color. Darkest specimens ochraceous except as follows: head, mesoscutum posteromedially, scutellum, outer surfaces hind femora and tibiae, tarsi, thoracic pleurae, propodeum and metasoma with dark brown hairs. Palest specimens will) all hairs while to pale ochraceous except fore and middle tibiae and hind basitibial plate with brown hairs. Most specimens have some combination intermediate between these extremes; usually hind tibial scopal hairs brown entirely or in part, rarely entirely pale or entirely dark brown.

MALE. MEASUREMENTS AND RATIOS. N = 20; length, 7-11 mm; width, 1.5-3.0 mm; wing length, M 3.44 0.248 mm. FL/FW, M = 0.85 0.004; FS1/FS2, M = 2.00 0.045.

INTEGUMENTAL COLOR. Black except as follows: mandible with apical third rufescent; flagellum below brown to dark brown; wing membranes hyaline, colorless, veins reddish brown to dark brown; tibial spurs testaceous; terga 1-5 blue-green, often with violaceous reflections, except narrow dark apical margins.

STRUCTURE. Antennae long, reaching midscutellum in repose; scape slightly longer than first two flagellar segments; flagellar segment 1 twice as long as segment 2 or almost so; segment 2 broader than long; segment 3 quadrate or longer; segments 4-11 longer than broad. Eyes each about three times as long as broad, inner margins diverging towards vertex. Mandibles long, decussate. Malar space as in female. Galea as in female but without short hooked hairs, shiny. Maxillary and labial palpi as in female. Prementum without hooked hairs; stipes and glossa as in female. Labral process as in female but apex broader, occasionally weakly emarginate apically, usually longer than basal width, shiny; labrum below process pointed medially, without distinct median crista, smooth, shiny. Clypeus and supraclypeal area as in female but punctures smaller. Face above antennal fossae as in female b rugulae often not reaching ocelli. Vertex as in female but often as tall as one ocellar diameter above lateral ocellus. Genal area in profile much broader than eye. broadest opposite middle of eye; sculptured as in female.

Pronotum laterally with humeral angle and dorsoventral ridge; sculptured as in female but more broadly shiny posterior to ridge. Thorax in general sculptured aim female except mesoscutal punctures more sparse.

Metasomal terga 1-5 as in female terga 1-4 but apical margins narrowly to broadly shiny, tessellation restricted to basal part of each apical area or absent. Tergum 7 without pygidium-like area. Sterna 2-5 with basal areas with sparse punctures; apical areas impunctate; surfaces reticularly shagreened. Sternum 6 broadly and shallowly emarginate apically, flat. Terminalia essentially identical to those of cryptanthae (Figs. 51-55).

VESTITURE. Darkest specimens with head hairs mostly brown but clypeus and supraclypeal areas pale medially, thoracic hairs white to pale ochraceous except small posteromedian mesoscutal brown patch, and tergum 7 with brown hairs. Pate specimens entirely white to pale ochraceous. Metasomal terga without pale fasciae: sterna without pale subapical fimbriae.

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Updated: 2021-05-13 13:30:53 gmt
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