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.
Please report text errors to: leah at discoverlife dot org.
Andrena pallidiscopa is a distinctive species of western North America. The male of pallidiscopa is readily recognized by the flat clypeus and the short, blunt, genal tooth just below the inferior mandibular articulation. The female of pallidiscopa has highly plumose, ochraceous to dark brown, scopal hairs and cuneate hind tibiae, a relatively flat clypeus, and a narrow space behind the pronotal dorsoventral ridge.
FEMALE. MEASUREMENTS AND RATIOS. — N = 20; length 8-11 mm; width, 2.5-3.5 mm; wing length, M = 3.58 ± 0.211 mm; FL/FW, M = 0.90 ± 0.004;FOVLfFOVW, M = 3.50 ± 0.062.
INTEGUMENTAL COLOR. — Black except as follows: mandible with apical half or more rufescent; flagellar segments 3-10 dark brown beneath; wing membranes hyaline, colorless to yellow, veins rufescent to dark brown; tergal apical areas translucent, yellow; sterna with apical areas hyaline; tibial spurs testaceous.
STRUCTURE. — Antennal scape length equals first four flagellar segments; segment 1 as long as next two and one-half segments; segments 2 and 3 slightly broader than long; segments 4-9 quadrate. Eyes each about three and three-fourths times as long as broad, inner margins converging slightly towards mandibles. Mandibles, malar space and galeae as in erigeniae. Maxillary palpus long, segmental ratio about u 0.9:1.0:0.9:0.7:0.6:0.7. Labial palpus with segmental ratio about as l.O:0.7:0.5;O.B. Labral process at least twice as broad as long, usually weakly emarginate apically; labrum apical to process flat, tessellate, without cristae. Clypeus relatively flit, punctures dense, separated by half a puncture width or less, surface dulled by Fine shagreening. Supraclypeal area minutely punctate and finely shagreened. Fact above antennal fossae with longitudinal rugulae reaching ocelli or almost so, with distinct interrugal punctures. Vertex above lateral ocellus equals about one ocellar diameter; opaque, finely tessellate. Facial fovea large, separated from lateral ocellus by more than one ocellar diameter, extending to below a line at lower margins antennal fossae. Genal area in profile broader than eye, with minute scattered punctures and fine shagreening dulling surface.
Pronotum laterally with distinct humeral angle, with dorsoventral ridge at least in upper half or more, depressed space posterior to ridge narrow; surface dulled by dense tessellation but moderately shiny posterior to ridge. Mesoscutum densely punctate; punctures small, separated mostly by half a puncture width or less; surface dulled by fine tessellation. Scutellum similar but often shiny anteromedially. Propodeum with dorsal enclosure dull, tessellate, with irregular to short longitudinal, weak rugulae in basal half or throughout; propodeum outside of enclosure dulled by close-set large punctures and fine tessellation. Mesepisternum with large crowded punctures and fine reticular shagreening dulling surface. Hind tibia cuneate.
Metasomal tergum 1 usually shiny, basal area with large punctures separated mostly by half to one puncture width; apical area punctures slightly smaller and surface moderately dulled by reticular shagreening; some specimens with entire tergum dulled by reticular shagreening. Terga 2 and 3 similar to 1 but punctures smaller and surfaces more often shagreened. Tergum 4 similar but surface usually reticularly shagreened. Tergum 5 basally with sparse punctures and fine tessellation. Pygidial plate V-shaped with rounded apex, internal raised triangular area well-separated from lateral margins, often lacking. Sterna 2-5 with basal area punctures separated by one puncture width or less, apical areas narrow, impunctate; surfaces at least moderately dulled by reticular shagreening.
VESTITURE. — White except as follows: vertex of head and thoracic dorsum ochraceous, metasomal terga 3 and 4 with short basal area hairs often brown in part; terga 5 and 6 with ochraceous to dark brown hairs; sternal hairs often brown; hind tibial scopal hairs ochraceous to dark brown, when pale usually brown on and below basitibial plates; tarsal vestiture often brown. Propodeal corbiculum incomplete anteriorly; internal hairs abundant, simple; dorsal hairs relatively short, plumose. Trochanteral flocculus incomplete basally. Hind femora with hairs not highly plumose but similar to those of fore and middle legs. Tibial scopal hairs highly plumose.
MALE. MEASUREMENTS AND RATIOS. — N = 20; length, 7-9 mm; width, 1.5-2.5 mm; wing length, M = 3.24 ± 0.192 mm; FL/FW, M = 0.86 ± 0.004; FS1/FS2, M = l.7 ± 0.033.
INTEGUMENTAL COLOR. — Black except as follows: mandible with apical fourth to one-third rufescent; flagellum dark brown below; wing membranes hyaline, colorless, veins reddish brown to brown; tergal apical areas and sternal apical areas translucent, rufescent towards base; tibial .spurs testaceous.
STRUCTURE. — Antennae moderately long, barely reaching scutellum in repose; scape length equals first two and two-thirds flagellar segments; flagellar segment 1 shorter than segments 2 plus 3; segments 2 and 3 about as long as broad (segment 3 occasionally slightly longer); segments 4-11 longer than broad. Eyes each about three and one-fourth times as long as broad, inner margins converging slightly towards mandibles. Mandibles long, not decussate. Galea and malar space as in female, labral process as in female but often slightly longer and apical margin often slightly thickened. Clypeus flat, sculptured as in female but punctures more dense. Maxillary palpus with segmental ratio about as 0.9:1.0:0.9:0.9:0.7:0.7. Labial palpus with segmental ratio about as 1.0:0.8:0.7:0.8. Supraclypeal area, face above antennal fossae and vertex as in female. Genal area in profile distinctly broader than eye (about as 3:2); broadly rounded posteriorly, broadest opposite upper third of eye; sculptured as in female short; short, often blunt process present just below inferior articulation of mandible.
Pronotum as in female but dorsoventral ridge almost complete. Thoracic sculpturing as in female but propodeal dorsal enclosure usually with a few to many short longitudinal rugulae; wing venation as in female.
Metasomal terga 1-5 with basal area punctures separated mostly by two to five puncture widths or more, surfaces moderately shiny to shiny, reticular shagreening weak to absent; apical areas impunctate, dulled by reticular shagreening, Tergum 7 without pygidium-like area. Sterna 2-5 with basal areas sparsely punctate; apical areas impunctate; surfaces dulled by coarse reticular shagreening. Sternum 6 with apical margin weakly reflexed, broadly emarginate. Penis valves elongate, narrow; dorsal lobe of gonocoxite elongate, acute. Sternum 7 bidentate. Sternum 8 with lip entire, broadened (Figs. 46-50).
VESTITURE. — Generally white or pale ochraceous; clypeal hairs dense, long; generally as in female but without pollen-collecting hairs and without dark brown hairs. Sterna without subapical fasciae.
Updated: 2021-05-08 13:12:16 gmt