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 light yellow throughout, and the vestiture of the metasoma, particularly that of tergum 2, places this species within the Citrinihirta group. However, the species is readily distinguished from all other Cnemidandrena by the deep, transverse depression posterior to the gradulus on metasomal terga 2 to 5.
FEMALE. MEASUREMENTS AND RATIOS. — N = 14; length, 7.3-9.0 mm; width, 2.5-3.1 mm; wing length, M = 3.50 ± 0.116mm;FL/FW, M = 1.07 ± 0.094; FOVL/FOVW, M = 2.99 ± 0.078.
INTEGUMENTAL COLOR. — Black except as follows: antenna dark brown beneath beyond second flagellar segment; mandible with apical half red; tibial spurs light white-yellow; mediotarsi, distitarsi and basal half of tarsal claws red-yellow, apical half of tarsal claws red; tegula hyaline light yellow-brown; wing veins and pterostigma light yellow; wing membrane with prominent dark spot in marginal area beyond marginal cell, remainder hyaline.
Metasomal terga with apical depressed area hyaline. Pygidial plate with apical half dark red, basal half red-yellow. Sterna widely hyaline apically.
STRUCTURE. — Scape slightly longer than flagellar segments 1 to 3; flagellar segment 1 slightly shorter than flagellar segments 2 plus 3; flagellar segment 2 shorter than flagellar segment 3. Eye a little less than 4 times longer than wide, with inner margin diverging very slightly above except for upper end somewhat incurved. Malar space 8 times wider than long or slightly less. 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; ventrobasal lamella well developed. Galea finely tessellate; dorsal surface nearly one-half wider than lateral surface. Maxillary palpus reaching to apex of galea, segmental ratio 0.9:1.1:0.7:0.7:0.6:0.6. Labial palpus with basal segment laterally compressed, slightly curved laterally, apical segment attached subapically, subapical segment weakly so; segmental ratio 1.4:0.8:0.5:0.7. Labral process flat, trapezoid, nearly 3 times wider than long, apical emargination very shallow, depth one-sixth or less length of labral process. Clypeus strongly protuberant; extending below eyes for two-fifths its length, with large punctures in median area except separated widely ventromedially leaving a small, impunctate area, punctures smaller, separated by one-half diameter laterally, with upper margin narrowly and lightly shagreened; remainder shiny. Supraclypeal area with medium-sized punctures 1 diameter apart, punctures roughened by moderate shagreening, shagreening reaching to eye. Vertex above lateral ocellus equal to 1 ocellar diameter, with medium-sized, deep punctures separated by 1 diameter, with light shagreening, surface shiny. Supra-antennal area longitudinally rugulate with interrugulae with medium-sized punctures. Facial fovea 3 times longer than wide, widest above, narrowing below, reaching above to a line equidistant between antennal fossa and upper margin of clypeus.
Pronotum with humeral angle and ridge weakly developed; humeral ridge crossed by prominent pronotal suture which extends well beyond humeral ridge; pronotum dorsally with medium-sized punctures separated by 1 diameter or less, punctures more widely separated laterally, sparse below pronotal suture, whole area shagreened. Scutum with medium-sized punctures separated by from one-half to 3 diameters, less than anterior half shagreened, remainder very shiny. Scutellum with medium-sized punctures sparse dorsally, closer on extreme posterior margin, dorsal area very shiny, posterior margin shagreened. Metanotum with medium-sized, deep punctures closely spaced except widely spaced on small, median area, with moderate shagreening. Propodeal enclosure with very irregular, prominent rugulae in about anterior half, weak tessellation in posterior half, with median, longitudinal area broadly depressed; dorsoposterior surface with medium-sized punctures separated by 1 diameter or less, dulled by weak tessellation; corbicular areas with medium-sized, widely spaced punctures in less than anterodorsal half, surface slightly dulled by light reticular shagreening. Mesepisternum with medium-sized punctures separated by 1 diameter, with moderate shagreening throughout. Metepisternum with very small punctures in upper half, weakly shagreened. Mesobasitarsus widely expanded, widest medially, 2.5 times longer than wide, wider than metabasitarsus. Metabasitarsus widest medially in basal third, dorsal edge nearly straight, less than 3.5 times longer than wide, three-fourths as wide as metatibia. Metatibia cuneate, widest distally, slightly curved ventrally, 3 times longer than wide. Tibial spurs normal. Wing with pterostigma 4 times longer than wide, vein 1st m-cu meets second submarginal cell one-third or more of distance from apex of cell.
Metasomal terga 2 to 5 with transverse areas posterior to gradulus broadly and deeply depressed below remainder of discs except less so on tergum 1, terga 1 to 4 with discs with medium-sized punctures, separated by 1 to 2 diameters except crowded apically. Tergum 5 with disc with large, deep punctures separated by less than 1 diameter. Terga 1 to 5 shagreened. Pygidial plate pointed apically with edges and median area raised, lateral edges concave; with small, close punctures except small, apical area shagreened. Sternum 1 with small, median, apical, V-shaped emargination medially, with small to medium-sized punctures separated by 2 diameters. Sterna 2 to 5 with transverse areas posterior to gradulus broadly and deeply impressed below remainder of sterna, sterna 2 to 6 with close, medium-sized to large punctures except on hyaline apical area; shagreened throughout.
VESTITURE. — White-yellow throughout. Clypeus with broad median area almost naked. Scutum, scutellum, and metanotum well covered with short, light yellow hairs. Propodeal corbicula with sparse, branched hairs in less than anterodorsal half. Trochanteral floccus imperfect. Metasomal tergum 1 densely covered with long hairs except as follows: hairs erect anteriorly, recumbent posteriorly forming a broad, apical fascia, small lateral patches of short, appressed hairs anterior to apical fascia; terga 2 to 4 with dense, apical fasciae of appressed hairs, fasciae obscuring half of terga; tergum 2 with long, erect hairs on narrow, median, longitudinal area and anteriorly on lateral margin of disc with small area between apical fascia and anterior, erect hairs of short, appressed hairs; remaining areas of terga 2 to 4 with very short, sparse, fine, erect hairs. Tergum 5 with long, white hairs not obscuring surface anteriorly. Sternum 1 with long, sparse, erect hairs medially, sterna 1 to 5 with apical fringes of short, white appressed hairs, very well developed on sternum 1, well developed on sterna 4 and 5, poorly developed on sterna 2 and 3; sterna 2 to 5 with subapical fimbriae not well developed; remainder of sterna 2 to 6 with short, sparse, nearly erect hairs.
MALE. MEASUREMENTS AND RATIOS. — N = 13; length, 5.9-7.0 mm; width, 2.0-2.6 mm; wing length, M = 2.94 ± 0.090 mm; FL/FW, M = 1.06 ± 0.102; FS1/FS2, M = 1.20 ± 0.046.
INTEGUMENTAL COLOR. — Black except as follows: antenna dark brown beneath beyond flagellar segment 1; mandible with a little more than apical third red; tibial spurs white tinged with yellow; tarsi and basal half of tarsal claws yellow, apical half of tarsal claws red; tegula shining brown, wing veins brown-yellow, pterostigma yellow; wing membrane with small, very narrow, marginal area beyond marginal cell very lightly shaded, remainder hyaline; metasomal terga with apical, depressed area hyaline, sterna widely hyaline apically.
STRUCTURE. — Scape equal in length to flagellar segments 1 plus 2 plus two-thirds of flagellar segment 3; flagellar segment 1 longer than flagellar segment 2, slightly longer than flagellar segment 3. Eye 3.5 times longer than wide, inner margin moderately diverging above except upper end subparallel or slightly incurved. Malar space, mandible, and galea as in female except mandible without ventrobasal lamella. Maxillary palpus with less than half apical segment projecting beyond apex of galea, segmental ratio 0.6:0.7:0.5:0.5:0.6:0.5. Labial palpus as in female except segmental ratio 1.1:0.5:0.4:0.6. Labral process trapezoid, weakly reflexed apically, 3 times wider than long, apical emargination depth one-fourth length of labral process. Clypeus strongly protuberant, extending below eyes for two-thirds its length, with large punctures, separated in lower half by 1 diameter, becoming crowded in upper half near upper edge, whole area shiny. Supraclypeal area sculptured as for upper margin of clypeus. Genal area a little less than 1.5 times wider than eye, with large, irregular, close punctures, posterior half shagreened, anterior half shiny. Vertex and supra-antennal areas as in female. Parocular areas with large, close punctures, surface shiny.
Pronotum with humeral angle and ridge well developed except humeral ridge a little depressed where crossed by prominent pronotal suture; with small punctures dorsally obscured by dense shagreening, small area below pronotal suture smooth, shiny. Remainder of mesosoma as in female except lateral corbicular area of pronotum sculptured as for dorsal surface.
Metasomal terga 1 to 5 as in female except depressed area on terga 2 to 5 more prominent; terga shiny. Sterna 1 to 6 as in female except depressed area more strongly developed, punctures slightly larger, deeper, with light shagreening. Sternum 7 (fig. 98) with basal apodemes narrowing anteriorly; apex pointed with long hairs laterally. Sternum 8 (fig. 99) with apex and neck region a little longer than basal region, apex scarcely expanded, neck narrow with abundant, long hair. Gonoforceps (figs. 95 to 97) in dorsal view with inner ridge not produced to outer edge; in ventral and lateral view with a small inner ridge near apex. Penis valves in dorsal and ventral view slightly expanded medially, median width equal to basal width; in lateral view downturned apically, as long as gonoforceps.
VESTITURE. — White-yellow throughout. Clypeus with dense pubescence obscuring surface. Mesosoma dorsally as in female.
Metasomal terga 1 to 5 with well-developed, apical fasciae obscuring more than half terga. Tergum 1 with long, erect hairs on remaining area, tergum 2 similar, hairs longest medially but shorter than median, erect hairs on tergum 1. Terga 3 to 5 with discs with short, erect hairs throughout, hairs shortest medially. Sternum 1 with sparse, long, erect hairs throughout, sterna 2 to 5 with strongly developed, apical fringes, remaining areas of sterna 2 to 6 with sparse, erect hairs.
VARIATION. — The propodeal enclosure varies in the degree of expression of the median longitudinal depression. In the holotype female from Ritzville, Adams Co., Washington, the depression is well developed with a carina anteriorly. One female from Wenatchee, Chelan Co., Washington, also has a short carina as in the female holotype, but another female from the same locality has a carina but the depression poorly developed, and another female from the same locality has the carina absent and the depression almost absent. The hair patterns on terga 1 and 2 are very similar in all female specimens, but the development of the tergal and sternal depressions varies somewhat. In males the sculpturing of the propodeal enclosure varies less than in females, but one male from Burntfork, Sweetwater Co., Wyoming, has the propodeal enclosure irregularly rugulate almost throughout and no obvious, median, longitudinal depression.