Text used courtesy of the Illinois Natural History Survey from:
LaBerge, W. E., Thorp, R. W., 2005. A revision of the bees of the genus Andrena of the Western Hemisphere. Part XIV. Subgenus Onagrandrena. Illinois Natural History Survey Bulletin 37: 1-63.
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Andrena decolorata is a second large pale species similar in color of the vestiture in both sexes to A. camissoniae. Like the previous three species decolorata has the pronotum with well-formed humeral angles and lateral ridges, the male mandibles decussate and the male genal area twice as broad as the eye in profile. This species can be told from camissoniae in both sexes by the propodeum being more declivous with a distinct dorsal surface lacking, terga 2-4 with basal areas having longer hairs (especially tergum 2), and the propodeum and mesepisterna being more finely sculptured as described below.
FEMALE: MEASUREMENTS AND RATIOS. — N = 7; length, 12-14 mm; width, 3.5-4.0 mm: WL, M = 4.36 ± 0.231 mm; FL/FW, M = 1.05 ± 0.007; FOVL/FOVW, M = 3.14 ± 0.076.
INTEGUMENTAL COLOR. Black except as follows: mandible with apical half rufescent; flagellum bright orange to red below; wing membranes hyaline, colorless or slightly infumate, veins red to reddish brown; metasomal terga with apical areas somewhat translucent, rufescent; tibial spurs yellow.
STRUCTURE. Antenna] scape as long as first four flagellar segments or almost so; flagellar segment I about as long as segments 2 plus 3 or slightly shorter, segment 2 slightly shorter than 3; segments 4-10 longer than broad. Eyes each about three and one-half times as long as broad, inner margins parallel. Mandibles long. moderately decussate, with distinct subapical tooth. Malar space linear, minimum length equal about one-tenth basal mandibular width. Galea pointed, broader near base, outer margin gently concave, weakly punctate, dulled by regular fine tessellation. Maxillary palpus long, extending beyond tip of galea by last two segments or more, segmental ratio about as 1.0: 1.0: 0.9: 0.7: 0.7: 0.8. Labial palpus with long curved first segment, segmental ratio about as 1.0: 0.5: 0.4: 0.5. Labral process (Fig. 23) large, apical part longer than broad, sides concave, weakly emarginate apically; labrum apical to process not sulcate, shiny. Clypeus shiny, with abundant small punctures separated by half puncture width or less except in impunctate midline, shagreened near base. Supraclypeal area dulled by fine shagreening and minute punctures. Face above antennal fossae longitudinally rugulate and punctate, surface moderately dulled, fossae separated from lateral ocellus by about hall an ocellar diameter. Vertex above lateral ocellus short, equal to about half an ocellar diameter or slightly more. Genal area in profile distinctly broader than eye (about as 7: 6), surface dulled by reticular shagreening, punctures minute, sparse.
Pronotum with humeral angles and lateral ridge, ridge not sharp or lamellate, surface dull, shagreened. Mesoscutum with minute round punctures separated by half to one puncture width, surface shagreened, dull. Scutellum similar but shagreening weaker. Metanotum densely punctate and shagreened. Propodeum with dorsal surface lacking, declivous from anterior margin; dorsal enclosure with weak rugulae but median rugula usually complete, shagreened; surface outside of enclosure with minute punctures separated by several puncture widths, surface dulled by shagreening. Mesepisterna sculptured similar to propodeum outside of dorsal enclosure. Fore wing with pterostigma narrow, long; vein first m-cu meets second submarginal cell beyond middle (usually near outer fourth).
Metasomal tergum 1 with apical area about as long as basal area, basal area punctures small, separated by one to three or four puncture widths, apical area punctate in basal half or more. punctures minute, surfaces dulled by coarse shagreening. Terga 2-3 with apical areas about as long as half of basal area, basal area punctures separated mostly by about 2 puncture widths or less, apical area punctate in basal half or slightly more, surfaces shiny, shagreening weak or absent. Pygidial plate with rounded apex, longer than broad at base, internal raised triangle weak, surface finely tessellate, dull. Sterna with basal areas distinctly punctate, apical areas impunctate, surfaces moderately shiny to dull, coarsely shagreened sternum 2 with long hairs of basal area similar to those of sternum 1.
VESTITURE. Almost entirely pale, pale ochraceous to ochraceous, darker above, head with reddish brown hairs on vertex, along inner margins of eyes and along outer margins of eyes at least above; facial fovea with tomentum reddish brown in upper half, pale ochraceous below. Propodeum with lateral corbicula not distinctly formed, internal hairs long, plumose; hind tibiae with scopal hairs long, simple, sparse; trochanteral flocculus complete, weak; metasomal terga without fasciae.
MALE: MEASUREMENTS AND RATIOS. — N = 16; length. 11.5-13.0 mm; width, 2.5-3.5 mm; WL, M = 3.79 ± 0.2«1 mm; FL/FW, M = 1.02 ± 0.006; FS1/FS2, M = 1.25 ± 0.028.
INTEGUMENTAL COLOR. Black except as follows: mandible with apical half or less rufescent; antennal flagellum reddish brown to brown below; wing membranes hyaline, colorless to slightly yellowed, veins red to reddish brown; metasomal terga with apical areas translucent, red to reddish brown; tibial spurs rufescent to testaceous.
STRUCTURE. Antenna moderately long, in repose reaches about midscutellum; scape length equals first two and one-third flagellar segments: flagellar segment I distinctly longer than segment 2 and about equal to segment 3, all segments longer than broad. Eyes each almost three and one-half times as long as broad in facial view, inner margins diverge slightly towards vertex. Mandibles decussate, subapical tooth present, small (Fig. 24). Galea as in female. Maxillary palpus as in female, segmental ratio not visible. Labial palpus as in female, segmental ratio about as 1.0: 0.6: 0.4: 0.6. Labral process large, about as long as broad, bidentate apically; labrum apical to process without sulcus or cristae. Clypeus sculptured as in female but lacking median impunctate line and punctures larger, surface shiny throughout. Supraclypeal area and face above antennal fossae as in female. Vertex above lateral ocellus equals to half an ocellar diameter or more but less than one diameter (allotype almost one). Genal area broad, with rounded knob about opposite midpoint of compound eye, surface sculptured as in female.
Pronotum with humeral angle and lateral ridge as in female. Mesoscutum, scutellum, metanotum sculptured as in female. Propodeum as in female but enclosure with slightly more rugulae near base (Fig. 25); mesepisternum with small round punctures separated by half to one and one-half puncture widths, interpunctural spaces finely tessellate. Wing venation as in female.
Metasomal tergum 1 sculptured as in female but somewhat shinier. Terga 2-5 sculptured as in female terga 1-4 but basal area punctures slightly denser, separated mostly by one to two puncture widths, apical area punctures restricted to basal half, surfaces shiny. Tergum 7 with extremely narrow pseudopygidial area, almost parallel-sided. Sterna 2-5 sculptured as in female but basal area punctures sparser and shagreening usually coarser. Genital capsule as shown (Fig. 26). Sterna 7 and 8 similar to rubrotincta but sternum 7 with apical lobes narrower and sternum 8 more distinctly capitate (Figs, 63 and 64).
VESTITURE. Pale ochraceous to ochraceous except as follows: brown to reddish brown across vertex, along inner margins eyes and in upper half along outer eye margins. Terga without apical pale fasciae; sterna with subapical fasciae present but weak, hairs relatively short; hind tibiae with hairs sparse, long, along anterior and posterior margins some hairs almost as long as dorsal femoral hairs: metasomal tergum 2 with basal area with long hairs longer than those of apical area and similar to those of tergum 1; terga 3 and 4 with basal area hairs decreasing in length.
TYPE MATERIAL. — The holotype female of Andrena (Onagrandrena) decolorata was collected 3 miles NE of Moreno, Riverside Co., California, April 5. 1963, by W. A. Steffan. The allotype male was collected 4 miles E of Elsinore. Riverside Co. in Railroad Canyon, April 14, 1965, by D. Veirs (Fig. 6). The holotype and allotype will be deposited in the collection of the California Academy of Sciences. Six female and 16 male paratypes (HCH, UCR, UCD, LACM. INHS) are as follows:
CALIFORNIA. RIVERSIDE CO.: Hemet: 1 female, April 26, 1961, from Cryptantha sp., Ewart and Browner; Millard Canyon: 1 female. April 1 8, 1968, from Madia (as Layia) exigua. Timberlake. SAN BERNARDINO CO.: Seeley Flats, San Bernardino Mts.: 1 female, July 3, 1917, H. Klotz.; 1 female, July 10, 1917, R. May. SAN DIEGO CO.: Descanso-Alpine Site: 1 male, March 17, 1972, from Cryptantha barbigera, A. R. Moldenke: 1 male, March 17. 1972. from Mirabilis californica (as laevis), A.R. Moldenke; 7 males, April 5. 1972, from Cryptantha intermedia, A.R. Moldenke; 1 male April 5, 1972, from Mirabilis californica (as laevis), A.R. Moldenke; 1 female, 1 male, April 5, 1972, from Salvia apiana, A.R. Moldenke; 1 male, April 19, 1972, from Cryptantha sp., A.R. Moldenke; 1 male, April 25, 1972, from Camissonia californica (as leptocarpa), A.R. Moldenke; Lakeside (2 mi. NE), March 13, 1968, J. Powell; Newton (8 mi. NW): 2 males, April 14, 1934, from Cryptantha intermedia, Timberlake. MEXICO. BAJA CALIFORNIA DEL NORTE: La Zapopita, Valle dc Trinidad: 1 female, April 9-14, 1961, F.S. Truxal.
FLORAL RECORDS. — Presumably this species is an oligolege of the genus Camissonia. It has been collected from flowers of plants listed below.
Camissonia californica (as leptocarpa), Cryptantha sp., C. barbigera, C. intermedia, Madia (as Layia) exigua, Mirabilis californica (as laevis). Saliva apiana.