Reprinted with permission of the University of Nebraska State Museum from:
LaBerge, W. E. 1967. A revision of the bees of the genus Andrena of the Western Hemisphere. Part I. Callandrena (Hymenoptera: Andrenidae). Bulletin of the University of Nebraska State Museum 7: 1-316.
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This Texan species is closely related to A. verecunda Cresson.
The female of afimbriata is distinctive in that the posterior hind tibial spur is bent and somewhat expanded near the base much as in subgenus Plastandrena, but not so strongly. The female of afimbriata also differs from that of verecunda by the facial fovea being nearer to the lateral ocellus, terga 1 and 2 having apical areas with punctures more crowded than in the basal areas and having weaker fasciae apically, and the scopal hairs being entirely white. The male can be readily separated from that of verecunda by the lack of dense subapical fimbriae on sterna 2-5.
FEMALE. MEASUREMENTS AND RATIOS. — N = 4; length, 14-15 mm; width, about 4.5 mm; wing length, M = 4.47 ± 0.302 mm; FL/FW, M = 1.00 ± 0.008; FOVL/FOVW, M = 2.15 ± 0.084.
INTEGUMENTAL COLOR. — Black except as follows: mandibles rufescent near tips; flagellar segments 4-10 dark red below; tegulae dark rufescent; wing membranes slightly infumate near tips, veins dark red to black; tergal apices 2-4 with apical areas slightly translucent, not hyaline; sterna rufescent, apices hyaline, yellow; tibial spurs orange-brown.
STRUCTURE. — Antennae short, scape longer than flagellar segments 1-3, shorter than segments 1-4; flagellar segment 1 as long as segments 2-4, segments 2 and 4 almost as long as 5 and slightly longer than 3. Eye longer than three and one-half times breadth, inner margins parallel or slightly converging towards mandibles. Malar space, mandibles and galeae as in verecunda. Maxillary palpus extending beyond galea by last palpal segments, segmental ratio about 1.3:1.4:1.0:1.0:0.6:0.6. Labial palpus as in verecunda but ratio about 1.5:1.0:0.7:0.6. Labral process, clypeus and supraclypeal area as in verecunda. Genal area slightly broader than eye in profile, sculptured as in verecunda but dulled by reticular shagreening posteriorly. Vertex above lateral ocellus equals one and one-third ocellar diameter, distinctly punctate except in area extending dorsolaterally from lateral ocellus, surface moderately shiny, coarsely and reticularly shagreened. Face above antennal fossae as in verecunda. Facial fovea of moderate length, extends below to about level of lower margin of antennal fossa, narrow below, broad and flattened above, separated from lateral ocellus by half an ocellar diameter or less.
Thoracic sculpturing as in verecunda except as follows: propodeal dorsal enclosure slightly roughened; corbicular area less shiny, shagreening slightly denser. Middle basitarsus narrower than hind, with parallel sides, anterior apical angle produced into a sharply pointed spine-like process. Wing venation as in verecunda. Claws normal. Posterior hind tibial spur bent near base and with narrow posterior membranous flange slightly expanded in this lower bend, entire spur bent in shallow S-shape.
Metasomal terga sculptured as in verecunda except as follows: tergum 1 with basal area punctures separated mostly by 2 to 3 puncture widths and apical area punctures by one puncture width or slightly more; terga 2-4 with apical area punctures distinctly more abundant than basal area punctures. Pygidial plate broad basally, V-shaped with narrowly rounded apex. Sterna as in verecunda.
VESTITURE. — Generally white to cinereous. Tergum 1 with sparse hails basally or none, apically without fascia although extremely weak hairs present laterally. Terga 2-5 with short suberect hairs basally; apically with decumbent hairs scarcely any longer or more plumose than basal hairs and not at all hiding surface, best developed on tergum 4. Terga 5 and 6 with long white hairs. Sterna 2-5 with apical fimbriae as in verecunda. Propodeal corbicula and trochanteral flocculus as in verecunda. Tibial scopal hairs plumose throughout. Inner surfaces tarsi light yellow; scopal hairs entirely white.
MALE. MEASUREMENTS AND RATIOS. — N = 6; length, 13-14 mm; width, 3.0-3.5 mm; wing length, M = 4.13 ± 0.062 mm; FL/FW, M = 1.06 ± 0.010; FS1/FS2, M = 2.61 ± 0.081.
INTEGUMENTAL COLOR. — As in female but flagellar segments 4-11 dark red below; sterna more piceous; distitarsi rufescent; tibial spurs pale yellow.
STRUCTURE. — Antennae short, in repose not reaching beyond middle of tegula; scape slightly longer than flagellar segments 1-3; flagellar segment 1 equal in length to segments 2-4, segments 2 and 3 slightly shorter than segment 4 which is slightly shorter than 5, segments 5-10 rectangular. Eye about three and one-half times as long as broad, inner margins converging slightly towards mandibles. Malar space, mandibles and galea as in female. Maxillary palpus as in female but ratio about 1.2:1.1:1.0:0.9:0.6:0.7, Labial palpus as in female but ratio about 1.5:1.0:0.6:0.7. Labrum, clypeus, supraclypeal area, genal area, vertex and face above antennal fossae as in female.
; Thoracic and metasomal sculpturing as in female except as follows: mesoscutum and scutellum slightly shinier; later surfaces of propodeum (= corbicular area) opaque, tessellate. Claws and tibial Spurs normal, posterior hind tibial spur not S-shaped, considerably longer than anterior spur. Wing venation as in female. Sternum 6 strongly reflexed apically, especially apicolaterally where margin is thick and well sclerotized, medially with broad shallow emargination.
Genitalia and sterna 7 and 8 (Figs. 169-172) similar to those of verecunda.
VESTITURE. — Generally white to cinereous. Terga 1-5 with weak apical fasciae usually broadly interrupted medially on terga 1-4. Sterna 2-5 without dense subapical fimbriae, subapical hairs sparse, weak, not strongly barbed. Inner surfaces tarsi pale yellow.
TYPE MATERIAL. — The holotype (SECK) female from Eldorado, Texas, was collected by R. H. and L. D. Beamer, C. D. Michener, J. G. Rozen and W. P. Stephen, April 10, 1950. The allotype (SECK) male and one male paratype were collected at the same time and place as the holotype on flowers of Pyrrhopappus carolinianus. In addition, 5 female and 3 male paratypes (SECK; INHS) from Texas are as follows: Giddings. 1 female and 1 male, April 12, 1953, R. H. Beamer, on Pyrrhopappus sp.; 1 male, April 12, 1953, R. H. Beamer, on Berlandiera sp. Paige. 2 females and 1 male, April 24, 1953, R. H. Beamer and L. D. Beamer, on Polygala alba.
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