Reprinted by permission of the Regents of the University of California from:
Thorp, R. W. 1969. Systematics and ecology of bees of the subgenus Diandrena (Hymenoptera: Andrenidae). University of California Publications in Entomology 52: 1-146.
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This species is most closely related to A. submoesta and more distantly to A. puthua. It may be distinguished from A. puthua by its larger size, by the broadly truncate apex of the labral process in the females, and by the flattened third antennal segment, recurved apex of the metasoma, and the broadly expanded apex of the last visible sternum in the males.
The males of A. blennospermatis and A. submoesta share the character of the expanded and flattened third antennal segment, a character which is unique in the subgenus Diandrena. The two species are separated by a number of character which appear as allometric expansions in A. blennospermatis associated with its larger size, but the gap in these characters is very distinct.
This species is ecologically similar to A. submoesta, but again gaps in ecological characteristics separate the two. A. blennospermatis flies earlier in the season in association with the early spring bloom of Blennosperma nanum and B. bakeri, which pollen analyses and field samples reveal to be the primary pollen soured for this bee. The floral structure in Blennosperma is very similar to that in Lasthenia and both genera are placed in the tribe Helenieae of the Compositae, the former however somewhat doubtfully.
FEMALE. — Integument olive-green; antenna basally and above apically dark brownish-black, apical 6 segments of antennal flagellum below yellow-brown, stigma of forewing and impunctate apices of metasomal terga yellow-brown, clypeus with moderately large, subapical, triangular dark area with violaceous reflections; pubescence pale, white on clypeus with some dark intermixed mediodorsally, dark on face, above and behind eye, white on antennal scape below, gena below and occiput, yellow-brown and dark intermixed on thoracic dorsum and upper pleurae, white on lower pleurae and legs except yellow-brown posteriorly on tibial scopa, white on metasoma, forming hair bands on apical segments, anal fimbria light brown; facial fovea with black sheen, tomentum pale brown. Head moderately shiny; moderately coarsely, sparsely punctate, with tessellate interspaces; clypeus, latero- and supraclypeal areas with punctures separated by one diameter; facial fovea extending from summit of eye to middle of antennal base; eyes slightly convergent below; antenna with segments 1 to 3 of flagellum as 13: 5: 5; labrum with process triangular, truncate, and transversely tumid apically (fig. 19); subgenal coronet long, well developed; gena moderately shiny, moderately coarsely punctate with tessellate interspaces, punctures separated by 1 to 2 diameters; pubescence of clypeus long, moderately dense, suberect. Mesosoma moderately dull, moderately coarsely punctate with tessellate interspaces; pronotum with punctures shallow, separated by 1 to 2 diameters, dorsolateral angle, right-angled with distinct lateral fold, posterior margin of pronotum slightly arched medially; mesoscutum with notaulus distinct; mesoscutum, scutellum, metanotum with punctures separated by slightly more than one diameter; propodeum moderately finely, sparsely punctate with tessellate-granular interspaces, punctures separated by 2 diameters, enclosure with few short rugulae along basal margin and long median longitudinal carina, otherwise shiny tessellate; episternum 2 coarsely punctate with roughened tessellate interspaces, punctures separated by one diameter; wing lightly infuscated, submarginals 1: 2 (36.5: 36), stigma : rest of marginal cell (16: 23), hind wing with jugal lobe broad and with incision between it and vannal, reaching beyond level of cu-v; posterior trochanter with long, curved, white, nearly perfect floccus, hairs at base of trochanter moderately long and somewhat straight; tibial scopa with dense, moderately long, finely branched hairs, nearly unbranched centrally on outer surface, posterior scopal hairs subequal in length to width of tibia at apex; pubescence of mesoscutum with many dense, moderately long yellow-brown hairs and few long dark hairs interspersed. Metasoma shiny, moderately finely, sparsely punctate with tessellate interspaces; basal elevation of first tergum with punctures separated by 2 to 4 diameters, basal elevations of terga 2 to 4 with punctures separated by 2 to 3 diameters, punctures closer on apical depressed margins; pubescence of basal elevation of tergum 1 moderately long, suberect, on basal elevations of terga, 2 to 4 moderately short, subdepressed; hairs longer, spatulate, and depressed on apical depressed margins forming hair bands, decreasingly medially, interrupted from tergum 1 to 3, complete on tergum 4. Length 8.5 to 9.5 mm, forewing 6.5 to 7 mm.
MALE. — Integument dark olive-green; antenna basally and above apically dark brownish-black, 7 to 8 flagellar segments below, stigma of forewing, apices of metasomal terga and sterna brown, clypeus with moderately large subapical triangular dark area with violaceous ions; pubescence pale, white except on mandible golden, narrow band laterally on face, and behind eye black. Head moderately shiny, moderately coarsely, closely punctate with late interspaces; clypeus, latero- and supraclypeal areas with punctures separated by less one diameter; parocular depression short, somewhat linear; eyes convergent below; antenna segments 1 to 3 of flagellum as 13:6:6; first flagellar segment flattened and widened, width: length (10: 13); labrum with process short, broad, with shallowly emarginate apex (fig. 20); mandibles long, decussate; gena dorsally moderately dull, moderately coarsely punctate with tessellate interspaces, punctures separated by slightly more than one diameter, ventroposteriorly shinier, with punctures sparser; pubescence of clypeus long, dense, subdepressed. Mesosoma dull, moderately coarsely, shallowly punctate with tessellate-scaly interspaces; pronotum finely punctate, transversely tessellate, dorsolateral angle right-angled with distinct lateral fold, posterior margin of pronotum nearly transverse; mesoscutum with notaulus distinct; mesoscutum, scutellum, metanotum with punctures separated by slightly more than one diameter; propodeum moderately coarsely, sparsely punctate with tessellate interspaces, punctures separated by two diameters, enclosure with few short rugulae along basal margin and long median longitudinal carina, otherwise shiny tessellate; episternum 2 coarsely punctate with roughened tessellate interspaces, punctures separated by one diameter; wing very lightly infuscated, submarginals 1:2 (34:35), stigma : rest of marginal cell (16:22); hind wing with jugal lobe broad and with incision between it and vannal, reaching beyond level of cu-v; pubescence long, sparse. Metasoma ovoid, strongly recurved ventrally at apex; moderately shiny, moderately finely, sparsely punctate with tessellate interspaces; first tergum with punctures moderately coarse, separated by 2 to 4 diameters, terga 2 to 5 with punctures finer, separated by 2 to 3 diameters; tergum 7 with somewhat broad, longitudinal, median elevation; sternum 8 (fig. 75); genital capsule (fig. 63); pubescence moderately long, erect on tergum 1, moderately short, suberect on terga 2 to 5, moderately long, weak hair bands laterally on terga 2 to 5. Length 7 to 8 mm, forewing 6 to 6.5 mm.
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