Reprinted with permission of the American Entomological Society from:
LaBerge, W. E. 1977. A revision of the bees of the genus Andrena of the Western Hemisphere. Part VIII. Subgenera Thysandrena, Dasyandrena, Psammandrena, Rhacandrena, Euandrena, Oxyandrena. Transactions of the American Entomological Society 103: 1-144.
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Except for the original description of the type series of Andrena serotina Robertson (nec Destefani, 1889) in 1893 and Dalla Torre's 1896 publication of the replacement name, Andrena robertsonii, all references to robertsonii probably refer to Andrena brevipalpis at least in part. Mitchell in 1960 recognized that two species were involved and named one of them A. dreisbachi. Unfortunately, Mitchell's dreisbachi is the same as Robertson's types of serotina ( = robertsonii). Therefore, the species Mitchell considered to be robertsonii should be called A. brevipalpis Cockerell. However, Mitchell did not distinguish the males of these two species, hence his records for robertsonii also include misdeterminations in part. In order to conserve space the literature citations to robertsonii are not listed under brevipalpis, although most of them refer to brevipalpis in part. They can be found in the synonymy of robertsonii.
Andrena brevipalpis is a small species with sparsely punctate clypeus and interrupted tergal bands. The female can be separated from the following species by the longer vertex, the shinier scutellum and metasomal terga, and the finely punctate first metasomal tergum. The males of brevipalpis have the first flagellar segment equal in length to one and one-third to one and one-half the length of the second segment (minimum lengths of each), the vertex short as in the female, and shinier, sparsely punctate terga as in the female.
FEMALE. MEASUREMENTS AND RATIOS. — N = 20; length, 8-10 mm width, 2.0-2.5 mm; wing length, M = 2.84 ± 0.135 mm; FL/FW, M = 1.08 ± 0.005; FOVL/FOVW, M = 4.45 ± 0.085.
INTEGUMENTAL COLOR. — Black except as follows: mandible with apical half or more rufescent; flagellar segments 4-10 and often apices of 2 and 3 yellow to red below; often rufescent along clypeal suture; tegula testaceous to piceous; wing veins brownish-red to red, membranes slightly infumate, yellow to brownish-yellow; terga 1-3 often slightly rufescent at least in part, apical areas hyaline, colorless at extreme apex to yellow basally; sterna 2-5 with narrow apical areas hyaline, piceous to rufescent basally; legs brown to black, distitarsi rufescent; tibial spurs pale.
STRUCTURE. — Antennal scape length equals first four flagellar segments or slightly less, flagellar segment 1 equal in length to segments 2 plus 3 which are each slightly broader than long and shorter than segment 4, segments 4-7 quadrate, 9-10 and often 8 longer than broad. Eyes each about three and three-fourths times as long as broad, inner margins parallel.
Malar space short, linear. Mandible short, in repose extending beyond midlabrum by one-fourth or less length of mandible. Galea short, broad, outer margin of apical half slightly concave to straight; surface moderately shiny to dull, finely reticularly shagreened. Maxillary palpus extended forward barely exceeds galea by last two segments; segmental ratio about as 1.0:0.8:0.7:0.6:0.5:0.5. Labial palpus with first segment slightly curved and flattened, segmental ratio about as 1.0:0.6:0.3:0.5. Labral process entire or weakly emarginate apically, trapezoidal or rounded, large, flat labrum apical to process without distinct cristae. Clypeus with sparse punctures except in lateral angles, punctures in median half separated mostly by two to five puncture widths, surface dull to moderately dull, reticularly shagreened. Supraclypeal area dulled by minute punctures and fine tessellation. Genal area in profile about as broad as eye, with fine punctures and shagreening except in shiny area near eye margin, lower surface dulled by coarse reticular shagreening and sparse punctures. Vertex above lateral ocellus equals one ocellar diameter or slightly less; dulled by shagreening and punctures; with distinct transverse impressed line above each lateral ocellus and meeting medially and connecting to a impressed line behind median ocellus. Face above antennal fossae rugulate with rugulae extending between fovea and lateral ocellus. Facial fovea shallow, long, narrow, extending below to a line below posterior margin of clypeus, separated from lateral ocellus by two-thirds an ocellar diameter or slightly more.
Pronotum normal, without humeral angle or ridge, with distinct impressed suture running from anteromedian margin to posterolateral margin. Mesoscutum with small shallow punctures separated mostly by one to two puncture widths or more, surface usually dulled by reticular shagreening, often moderately shiny posteromedially. Scutellum similar but more often shiny medially. Propodeum with dorsal enclosure roughened by fine irregular rugulae throughout (holotype) or at least in basal half or more; dorsal surface outside of enclosure and posterior surface opaque, coarsely tessellate with obscure punctures; lateral surface slightly shiny, evenly tessellate with sparse piliferous punctures. Mesepisternum opaque, tessellate with obscure punctures. Pterostigma broader than from inner margin prestigma to anterior wing margin; vein 1st m-cu meets second submarginal cell in outer third or less of cell.
Metasomal tergum 1 shiny, with small, distinct punctures separated mostly by one to two or three puncture widths; surface unshagreened or only delicately so. Terga 2-4 similar but shagreening becoming progressively denser posteriorly so that tergum 4 dull to moderately shiny. Pygidial plate V-shaped with rounded apex and distinct raised internal triangular area. Sterna 2-5 impunctate at extreme bases, elsewhere with punctures separated by one to two punctures widths (sparser on tergum 2), surfaces moderately dulled by reticular shagreening.
VESTITURE. — Generally pale ochraceous to ochraceous except as follows terga 5 and 6 usually brown medially; basitibial plate brown; inner surfaces tarsi pale yellow. Clypeal hairs short, sparse; mesoscutal and scutellar hairs short, sparse; tergum 2 with apical pale fascia interrupted medially; tergum 3 with apical band usually interrupted medially at least narrowly (complete in holotype); tergum 4 with apical band usually complete; terga 2-4 with discal hairs sparse, fine, simple, pale, decumbent. Pollen-collecting hairs as in Thysandrena but tibial scopal hairs relatively sparse, not completely obscuring surface.
MALE. MEASUREMENTS AND RATIOS. — N = 20; length, 7-9 mm; width, 1.5-2.0 mm; wing length, M = 2.72 ± 0.143 mm; FL/FW, M = 1.18 ± 0.012; FS1/FS2, M = 1.45 ± 0.029.
INTEGUMENTAL COLOR. — Black except as follows: mandible dark rufescent at least in apical half; clypeus bright yellow except narrow anterior margin and maculae below anterior tentorial pits; flagellar segments 3-11 and often apices of 1 and 2 red to yellow below; wing veins red, membranes moderately infumate, yellow; metasomal terga 1-5 narrowly hyaline apically, often somewhat rufescent especially on terga 1 and 2; sterna dark rufescent to piceous with hyaline apical margins; legs dark rufescent to black; distitarsi rufescent.
STRUCTURE. — Antenna of moderate length, in repose not reaching beyond scutellum; scape length equal to about length of first two and two-thirds flagellar segments; flagellar segment 1 always longer than segment 2 and usually slightly longer than 3 which in turn is longer than 2; segment 2 broader than long, remaining segments longer than broad. Eyes each two and one-half times as long as broad or slightly shorter, inner margins parallel. Mandible and galea as in female. Maxillary palpus as in female but segmental ratio about as 1.0:1.0:0.7:0.6:0.5:0.7. Labial palpus as in female but ratio about as 1.0:0.6:0.5:0.4. Labral process weakly emarginate apically, trapezoidal with rounded apical corners, shiny labrum below process shiny, without cristae. Clypeus as in female but punctures separated mostly by one to two puncture widths and often slightly shinier. Supraclypeal area and genal area as in female. Vertex moderately long, above lateral ocellus usually slightly shorter than one ocellar diameter (about as 9:10) or about equal, sculptured as in female. Face above antennal fossae rugulate as in female but rugulae coarser.
Thoracic form and sculpturing as in female but mesoscutum more often shiny posteromedially and scutellum usually shiny except peripherally. Wing venation as in female.
Metasomal tergum 1 as in female; terga 2-5 as in female terga 2-4; sterna 2-5 with discs with sparse punctures separated mostly by two to three puncture widths. Sternum 6 with apical margin thickened, strongly and abruptly reflexed, with apicolateral angles forming blunt, dark teeth. Terminalia as in Figures 89-93.
VESTITURE. — Generally as in female but lacking pollen-collecting hairs except as follows: terga 2-5 with discs with fine, suberect, pale, almost simple hairs, with apical pale fasciae lacking or restricted to short lateral fasciae; terga 6 and 7 pale; sterna 2-5 lacking subapical fimbriae or these consist of a single row of short suberect hairs.
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