Reprinted by permission of the Regents of the University of California from:
Donovan, B. J. 1977. A revision of North American bees of the subgenus Cnemidandrena (Hymenoptera: Andrenidae). University of California Publications in Entomology: 1-107.
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The vestiture is wholly white throughout, a character which separates this species somewhat from the other species within the Citrinihirta group, but the general integumental sculpture and the metasomal vestiture, particularly that on tergum 2, shows that this species lies within the Citrinihirta group.
FEMALE. MEASUREMENTS AND RATIOS. — N = 19; length, 6.6-7.8 mm; width, 2.1-2.5 mm; wing length, M = 2.21 ± 0.072 mm; FL/FW, M = 1.08 ± 0.104; FOVL/FOVW, M = 3.34 ± 0.304.
INTEGUMENTAL COLOR. — Black except as follows: antenna becoming lighter beyond second flagellar segment to medium brown apically; mandible with apical half red; tegula hyaline light brown, wing veins brown, pterostigma light yellow, wing membrane moderately clouded apically, remainder hyaline; tibial spurs white tinged with yellow; mediotarsi, distitarsi lightly yellowed apically, tarsal claws with basal half yellow, apical half red; metasomal terga with depressed apical margin hyaline; pygidial plate red; sterna widely hyaline apically.
STRUCTURE. — Scape equal to flagellar segments 1 to 3; flagellar segment 1 equal to flagellar segment 2; flagellar segment 2 slightly shorter than flagellar segment 3. Eye 4 times longer than wide with inner margin diverging slightly above except for upper end somewhat incurved. Malar space 7 times wider than long. Mandible in repose extends for a little less than one-fourth its length beyond middle of labrum, with notch of mandible tooth equidistant between middle of labrum and mandible apex. Galea moderately tessellate, dorsal surface twice as wide as lateral surface. Maxillary palpus reaching to apex of galea, segmental ratio 0.7:0.9:0.6:0.6:0.4:0.5. Labial palpus with basal segment laterally compressed and curved, apical segment attached subapically, segmental ratio 1.2:0.8:0.6:0.7. Labral process flat, twice as wide as long, apical emargination small, depth one-fifth length of labral process. Clypeus strongly protuberant, extending below eyes for slightly less than one-half its length, evenly rounded from side to side; broad, median, lower area nearly impunctate, lateral upper areas with large punctures separated by 1 diameter, punctures becoming smaller near upper periphery, upper periphery narrowly and weakly to moderately shagreened, remainder shiny. Supraclypeal area with medium-sized, irregular punctures obscured by moderate shagreening. Genal area 1.5 times wider than eye, with medium-sized punctures separated by 2 diameters, with weak, reticular shagreening except for narrow, shiny area near eye. Vertex above lateral ocellus equal to 1 ocellar diameter, with medium-sized punctures separated by 1 diameter but somewhat obscured by moderate shagreening. Supra-antennal area with longitudinal rugulae and indistinct, interrugal punctures. Facial fovea nearly 3.5 times longer than wide, rounded above, narrowed and somewhat pointed below, reaching above to a line just above median ocellus, reaching below to a line one-third of distance between antennal fossa and clypeus from antennal fossa.
Pronotum with humeral angle moderately developed; humeral ridge weakly developed, depressed where crossed by pronotal suture; with small, indistinct punctures dorsally; whole area moderately shagreened. Scutum with medium-sized punctures separated by 3 diameters, small dorsal median area shiny, remainder shagreened. Scutellum with anterior two-thirds or more nearly impunctate, shiny, remainder with irregular punctures obscured by moderate shagreening. Metanotum with medium-sized punctures separated by 1 to 2 diameters, densely shagreened. Propodeal enclosure with irregular rugulae in anterior two-thirds, remainder weakly tessellate with a broad, longitudinal, median depression; dorsoposterior areas with medium-sized punctures separated by 1 or more diameters, weakly tessellate; corbicular areas with scattered, medium-sized punctures in anterodorsal third or slightly more, with weak shagreening, nearly shiny. Mesepisternum with medium-sized punctures separated by 1 diameter, except narrow, posterior area nearly impunctate, whole area moderately shagreened. Metepisternum weakly shagreened, nearly shiny. Mesobasitarsus widest medially, slightly less than 2.5 times longer than wide, wider than metabasitarsus. Metabasitarsus widest medially in anterior third, 4 times longer than wide, less than two-thirds width of metatibia. Metatibia cuneate and curved, widest apically, more than 3 times longer than wide; tibial spurs normal. Wing with pterostigma 4 times longer than wide, vein 1st m-cu meets second submarginal cell less than one-fourth of basal distance of cell from cell apex.
Metasomal terga 1 to 4 with apices of discs with broad bands of medium-sized punctures separated by 1 diameter, tergum 1 with punctures laterally and anteriorly, remaining areas of discs on terga 1 to 4 with small punctures and moderate to light shagreening. Tergum 5 with disc with large punctures separated by less than 1 diameter. Pygidial plate very narrowly rounded apically, sides narrowly raised, narrow, median, longitudinal area moderately raised. Sternum 1 with narrow, V-shaped, median emargination with anterior angle acute, with medium-sized, irregularly spaced punctures, weakly shagreened; sterna 2 to 6 with small punctures separated by 2 to 3 diameters except sterna 3 to 5 with anterior, median, impunctate areas narrowing posteriorly to apical margins, very weakly shagreened, shiny.
VESTITURE. — White throughout. Clypeus with broad, median two-thirds naked or nearly so. Scutum with hairs sparse dorsally. Scutellum with anterior, impunctate area naked. Propodeal corbicula with scattered, long, erect hairs in anterodorsal third or slightly more. Trochanteral floccus imperfect.
Metasomal terga 1 to 4 with apical fasciae of appressed hairs, fasciae obscuring one-half or slightly less of terga; tergum 1 with fascia less dense than on terga 2 to 4, with long, erect hairs medially anterior to apical fascia, shorter hairs laterally and anteriorly; discs of remaining terga with very sparse, very short, fine hairs. Tergum 5 obscured by long, dense, posteriorly directed hairs. Sternum 1 with well spaced, long, erect hairs medially; sterna 2 to 5 with moderately dense, apical fringes, with subapical fimbriae weak laterally, absent in median thirds; remainder of sternal punctate areas with short, sparse, erect hairs.
MALE. MEASUREMENTS AND RATIOS. — N = 5; length, 5.3-5.9 mm; width, 1.70 mm; wing length, M = 1.84 ± 0.036 mm; FL/FW, M = 1.03 ± 0.067; FS1/FS2, M = 1.23 ± 0.074.
INTEGUMENTAL COLOR. — Black except as follows: antenna light brown beneath beyond second flagellar segment; mandible with apical third red; tegula hyaline dark brown, wing veins medium brown, pterostigma yellow, wing membrane very faintly darkened apically, remainder hyaline; tibial spurs white, tinged lightly with yellow; mediotarsi, distitarsi and tarsal claws as in female; metasomal terga with apical, depressed area hyaline, sterna widely hyaline apically.
STRUCTURE. — Scape longer than flagellar segments 1 to 3; flagellar segment 1 a little longer than flagellar segment 2, equal to flagellar segment 3. Eye 3.3 times longer than wide with inner margin diverging above except for upper end somewhat incurved. Malar space 8 or more times wider than long. Mandible in repose extends for one-third its length beyond middle of labrum with notch of mandible tooth equidistant between middle of labrum and mandible apex. Galea with dorsal surface one-half wider than lateral surface, moderately finely tessellate. Maxillary palpus projecting a little beyond apex of galea; segmental ratio 0.7:0.6:0.6:0.5:0.5:0.5. Labial palpus as in female except segmental ratio 1.1:0.6:0.5:0.5. Labral process with apical half moderately reflexed, twice as wide as long, apical emargination depth one-third length of labral process. Clypeus moderately protuberant, extending below eyes for a little less than half its length, with large punctures, widely spaced in lower median area, crowded above and laterally, shiny. Supraclypeal area with crowded, medium-sized punctures, shiny. Genal area twice as wide as eye, produced to an angle opposite midpoint of eye with weak, rounded ridge above eye, with small to medium-sized punctures separated by 1 to 2 diameters, about posterior half with light, patchy shagreening, remainder shiny. Vertex, supra-antennal area as in female with parocular areas as for supra-antennal area.
Pronotum with humeral angle and ridge well developed, humeral angle scarcely depressed where reached by weak, pronotal suture; area above humeral angle strongly shagreened, area below shiny. Remainder of mesosoma as in female except as follows: scutum with dorsal, shiny area larger; lateral area of propodeum with scattered, large punctures in about dorsal half.
Metasomal terga 1 to 5 with medium-sized punctures on discs separated by 1 to 2 or more diameters, surface shiny. Sternum 1 with small, apical, V-shaped emargination with anterior angle acute, with widely spaced, medium-sized punctures; sterna 2 to 6 with small punctures, anteriorly 2 diameters apart but punctures very sparse posteriorly. Sternum 7 (fig. 93) with basal apodemes of equal width throughout, rounded basally; apex truncate with long hairs on lateral angles. Sternum 8 (fig. 94) with apex and neck region equal in length to basal region, apex moderately expanded, neck of equal width throughout with abundant, long hairs. Gonoforceps (figs. 90 to 92) in dorsal view ridged obliquely with weak ridge reaching outer edge, ventrally ridged near apex. Penis valves widest medially, narrowing apically to slightly expanded apex.
VESTITURE. — White throughout. Clypeus obscured by moderately dense, long pubescence. Scutum nearly naked dorsally.
Metasomal terga 1 to 5 with apical fasciae of short, recumbent hairs, fasciae obscuring a little less than half of terga; fascia of tergum 1 less dense than remaining fasciae; remainder of discs of terga 1 to 5 with erect hairs, long on tergum 1, shorter on tergum 2, shorter still on terga 3 to 5. Sternum 1 with sparse, long, erect hairs, sterna 2 to 5 with well developed, thick, apical fringes, remainder of sternal areas with short, erect, sparse hairs to nearly naked anteriorly.
VARIATION. — In females the shape of the facial foveae above varies slightly from one individual to another. One female from Purdy, Washoe Co., Nevada, has the clypeus with slightly more than half its length projecting below the eyes. One female and 1 male from Reno, Washoe Co., Nevada, have the pubescence tinged with yellow and the tergal fasciae thicker than other specimens, and the mediotarsal and distitarsal segments are yellow throughout. One male from 24 km S. Headquarters Malheur Refuge, Harney Co., Oregon, has the pro- mediotarsi and -distitarsi normal, the meso- mediotarsi and -distitarsi more yellow, and the meta- mediotarsi and -distitarsi light yellow.