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 yellow pubescence with black hairs on metasomal tergum 5 and the wings with a very dark, apical spot readily separate A. surda from other species of Cnemidandrena. Its closest relative seems to be A. luteihirta which is similarly colored except that A. luteihirta has the pubescence citrus yellow throughout.
FEMALE. MEASUREMENTS AND RATIOS. — N = 20; length, 8.6-11.2 mm; width, 2.9-3.5 mm; wing length, M = 3.22 ± 0.195 mm; FL/FW; M = 1.03 ± 0.017; FOVL/FOVW, M = 2.94 ± 0.190.
INTEGUMENTAL COLOR. — Black except as follows: antenna red-brown ventrally beyond second flagellar segment; mandible with apical half red; tibial spurs light yellow; mediotarsi, distitarsi yellow; tegula shining brown; wing veins red-brown, wing membrane with very dark, almost black apical stigma; metasomal terga with wide apical depressed area hyaline, sterna with apical margin hyaline.
STRUCTURE. — Scape a little longer than flagellar segments 1 to 3; flagellar segment 1 subequal to flagellar segments 2 plus 3; flagellar segments 2 and 3 equal in length. Eye less than 3 times as wide as long, inner margin slightly diverging above except upper end incurved. Malar space extremely short, almost 10 times as wide as long. Mandible in repose extends for one-third its length beyond middle of labrum; notch of mandible tooth equidistant between middle of labrum and mandible apex. Galea moderately tessellate, lateral surface narrower than dorsal surface. Maxillary palpus reaching to apex of galea; segmental ratio 0.8:0.9:0.7:0.7:0.7:0.7. Labial palpal basal segment moderately compressed and curved laterally, apical segment attached subapically, segmental ratio 0.3:0.6:0.5:0.5. Labral process less than twice as wide as long, weakly reflexed, apical emargination depth equal to one-third length of labral process. Clypeus moderately protuberant, extending for about one third its length below eyes, with round, coarse punctures except for a small, median, impunctate, polished area; punctures separated by 1 diameter medially, becoming somewhat smaller, more crowded, obscured by dense shagreening in dorsolateral half. Supraclypeal area with irregular longitudinal rugulae interrupting small punctures. Genal area 1.5 times as broad as eye; narrow shiny area near eye margin with small, shallow punctures separated by 1 to 4 diameters, remaining area shagreened. Vertex above lateral ocellus equals 1.5 ocellar diameters, coarsely tessellate with prominent punctures separated by one-half diameter. Supra-antennal area with longitudinal rugulae, with medium to large interrugal punctures. Facial fovea more than half length of eye, 3 times as long as broad, rounded above, narrowed below, reaching above to a line through lower edge of lateral ocellus and below to lower margin of antennal fossa.
Pronotum with humeral angle and ridge moderately developed, pronotal suture crossing humeral angle, shagreened throughout with small, weak punctures dorsally; scutum densely tessellate, with scattered punctures of irregular diameter. Scutellum densely tessellate in posterior half with large punctures; small, nearly polished area anteriorly. Metanotum with very large punctures interrupted by dense tessellation. Propodeal enclosure tessellate laterally and posteriorly; central triangular area irregularly rugulate. Propodeal dorsoposterior surfaces tessellate with obscure punctures, lateral corbicular surfaces with coarse, reticular shagreening and medium-sized, widely spaced punctures in anterior fourth. Mesepisternum with moderate tessellation, crowded punctures above, becoming separated by 5 diameters below. Metepisternum shagreened, impunctate. Mesobasitarsus widest medially, equal in width to metabasitarsus, more than 2.5 times longer than wide. Metabasitarsus nearly 2.5 times longer than wide. Metatibia widest distally, narrowing sharply basally, more than one-fourth wider than meso- and metabasitarsus, 3 times longer than broad, Pterostigma more than 4 times longer than broad; vein 1st m-cu meets second submarginal cell well beyond middle.
Metasomal terga 1 to 4 with discs tessellate and medium-sized punctures separated by 3 to 6 diameters, but by 1 to 3 diameters on apical margins of discs. Tergum 5 with weak tessellation, punctures more prominent; posterior rim raised and thickened on more posterior punctures; punctures on disc separated by 2 to 4 diameters; on apical margin by one-half diameter or less. Apical areas of terga 1 to 5 shagreened. Pygidial plate smooth but dull, V-shaped, apex somewhat reflexed, edges anterior to reflexed area raised. Sternum 1 with small, median, V-shaped apical emargination, sterna 1 to 6 with small to medium-sized punctures separated by 2 diameters, lightly shagreened.
VESTITURE. — Yellow except as follows: facial fovea with hairs white-yellow; metafemoral apical fimbria, basitarsi, and metasomal terga and sterna 5 and 6 black. Clypeus with narrow, median, longitudinal area naked or nearly so, hairs abundant laterally. Scutum with hairs short, moderately dense. Scutellum with anterior half or slightly less naked or nearly so. Propodeal corbicula with anterodorsal fourth with long, widely spaced hairs. Trochanteral floccus imperfect.
Metasomal terga 1 to 4 with broad, dense, appressed apical fasciae covered half or a little more of terga; remaining areas with long, erect hairs dense laterally, longest medially on tergum 1, shorter on posterior terga. Tergum 5 nearly obscured by long, dense, posteriorly directed hairs. Sternum 1 with long, well spaced, erect hairs; sterna 1 to 5 with apical fringes, poorly developed in about median thirds; well developed laterally; sterna 2 to 5 with subapical fimbriae similar, short, erect, widely spaced hairs on remaining area.
MALE. MEASUREMENTS AND RATIOS. — N = 20; length, 7.2-10.7 mm; width, 2.2-3.1 mm; wing length, M = 2.86 ± 0.213 mm; FL/FW, M = 1.00 ± 0.028; FS1/FS2, M = 1.25 ± 0.079.
INTEGUMENTAL COLOR. — Black except as follows: antenna dark grey-brown beyond first flagellar segment; mandible with apical third red; remainder as in female.
STRUCTURE. — Scape longer than flagellar segments 1 plus 2; flagellar segments 1 and 2 equal in length, shorter than succeeding segments. Eye almost 3.5 times as long as broad, inner margin diverging slightly above except for upper end slightly incurved. Malar space, mandible, and galea as in female except mandible without ventrobasal lamella. Maxillary palpus projecting slightly beyond apex of galea; segmental ratio 0.7:0.9:0.7:0.6:0.6:0.6. Labial palpus as in female except segmental ratio 1.0:0.6:0.3:0.5. Labral process strongly reflexed, length three-fourths width, apical emargination depth one-third length of labral process. Clypeus shining, noticeably protuberant; extending for one-third its length beyond lower level of eyes, with coarse punctures separated by one-half diameter except for small impunctate area medioventrally. Supraclypeal area as in female; rugulae extending laterally to parocular areas with punctures interrupting rugulae above a line above antennal fossa. Genal area twice as wide as eye, weakly angulate to rounded posteriorly, sculptured as in female except shiny area near eye wider, remaining area coarsely shagreened. Vertex as in female. Thorax sculptured as in female except as follows: humeral angle and ridge more prominent with dorsal half of area posterior to humeral ridge with longitudinal rugulae, shagreening more dense than in female; anterior half of scutellum impunctate, polished; lateral face of propodeum moderately tessellate with scattered punctures, punctures more numerous in dorsal half. Wing as in female.
Metasomal terga 1 to 5 with discs irregularly tessellate with scattered punctures separated by 4 to 6 diameters, but more dense posteriorly; depressed apical margins smooth, polished. Sterna 1 to 6 finely shagreened with small punctures separated by 2 to 6 diameters. Sternum 1 with deep, V-shaped apical median emargination; sternum 2 with broad, shallow, apical median emargination. Sternum 7 (fig. 113) with apex broadly truncate, long hairs projecting posteriorly; basal apodeme narrowing anteriorly. Sternum 8 (fig. 114) with apex truncate, expanded, apex and neck region equal to basal region; apex and neck with abundant, long hairs extending laterally onto basal region. Gonoforceps (figs. 110 to 112) in dorsal and ventral views flattened and expanded apically; in lateral view appearing narrowed. Penis valves expanded laterally, expansions blunt at tip; penis strongly bent downwards.
VESTITURE. — Yellow throughout, slightly less colored ventrally. Metasomal hair distribution as in female except hairs on tergum 5 similar to hairs on terga 3 to 4. Sternal hairs longer than in female, apical fringes strongly developed, not appressed.
VARIATION. — In females a very few, fine hairs may be present on the medioventral clypeal area. The propodeal enclosure may be depressed medially. In both sexes the wing membranes may appear slightly infumate throughout; the integument may be red-brown or dark red-brown throughout; mediotarsi and distitarsi are often very yellow. In males, the anterior half of the scutellum may be lightly shagreened; sternum 7 apically varies from somewhat emarginate to convex.