Reprinted with permission of the American Entomological Society from:
Bouseman, J. K., LaBerge, W. E. 1978. A revision of the bees of the genus Andrena of the Western Hemisphere. Part IX. Subgenus Melandrena. Transactions of the American Entomological Society 104: 275-390.
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Andrena regularis is a large northern species related to A. carlini which it resembles in general habitus. The female of regularis can be separated from that of carlini by its sparse clypeal punctation and acutely V-shaped pygidial plate. The male of regularis can be distinguished from that of carlini by its shiny clypeus with regularly spaced, round punctures. The male sixth sternum lacks the raised subapical triangular area and the hairs are only moderately long, not formed into a long dependent tuft.
FEMALE. MEASUREMENTS AND RATIOS. — N = 20; length, 11-13 mm; width, 3.5-4.5 mm; wing length, M = 5.21 ± 0.104 mm; FL/FW, M = 0.96 ± 0.003; FOVL/FOVW, M = 2.90 ± 0.032.
INTEGUMENTAL COLOR. — Black except as follows: mandible with rufescent reflections to base; flagellar segments 2 or 3 to 10 reddish-brown below; tegulae reddish-brown; wing membranes moderately infumate, yellowish-brown, veins reddish-brown; terga and sterna often with rufescent reflections; distitarsi rufescent; tibial spurs reddish-brown to testaceous.
STRUCTURE. — Antennal scape as long as first three and one-half flagellar segments or slightly longer; flagellar segment 1 as long as segment 2 plus two-thirds of segment 3; segment 2 about as long as 3, as long as broad and shorter than 4; segments 4-9 longer than broad. Eyes each three and three-fourths times as long as broad or slightly longer, inner margins parallel. Mandible, galea and stipes as in carlini. Maxillary palpus as in carlini but segmental ratio about as 0.9:1.0:0.9:0.8:0.5:0.6. Labial palpus as in carlini but ratio about as 1.0:0.7:0.5:0.5. Labral process and labrum below process as in carlini. Clypeus shiny except shagreened in basal third or less; with small round punctures separated by one to two or more puncture widths, without median impunctate line. Supraclypeal area and face above antennal fossae as in carlini. Facial fovea as in carlini but separated from lateral ocellus by one-half to two thirds an ocellar diameter. Vertex above lateral ocellus equals two ocellar diameters or slightly less, sculptured as in carlini. Genal area in profile one and three-fourths times as broad as eye or slightly more, surface dulled by reticular shagreening and minute obscure punctures, usually shagreened to eye margin.
Thoracic form and sculpturing as in carlini but propodeal dorsal enclosure minutely roughened in basal half or more and lateral surface without vermiculate rugulae posteriorly. Wing venation as in carlini but second submarginal cell usually markedly shorter along anterior margin than along posterior margin.
Terga and sterna as in carlini but terga often less shiny. Pygidial plate narrow, V-shaped with acute apex.
VESTITURE. — Generally as in paler specimens of carlini but dark hairs appear more often brown than black.
MALE. MEASUREMENTS AND RATIOS. — N = 20; length, 8.5-12.0 mm; width, 2.5-4.0 mm; wing length, M = 4.38 ± 0.197 mm; FL/FW, M = 0.93 ± 0.004; FS1/FS2.M = 1.42 ± 0.017.
INTEGUMENTAL COLOR. — Black except as follows: mandible with apical fourth rufescent; flagellar segments 3-10 dark brown to reddish-brown below; tegula rufescent; wing membranes hyaline, veins reddish-brown; terga usually with rufescent reflections basally, apical areas slightly translucent; sterna 2-5 with apical areas hyaline, colorless, with rufescent reflections basally; distitarsi and often hind basitarsi and tibiae with rufescent reflections; tibial spurs testaceous to ferruginous.
STRUCTURE. — Antenna moderately long, in repose reaching middle of scutellum; scape length equals First two and one-half flagellar segments; flagellar segment I equal to segment 2 plus half of 3, usually slightly longer than segment 3; segments 3-10 each almost one and one-half times as long as broad. Eyes each about three and one-half times as long as broad, inner margins parallel. Mandible and galea as in carlini. Maxillary palpus as in carlini but segmental ratio about as 0.8:1.0:0.8:0.7:0.6:0.6. Labial palpus as in carlini but ratio about as 1.0:0.6:0.5:0.5. Labral process entire, thickened, trapezoidal with rounded apicolateral angles, broader than long; labrum below process punctate, not sulcate. Clypeus short but longer than one-third minimum interocular distance, shiny and unshagreened except at extreme base, with round deep punctures regularly spaced about half a puncture apart or slightly more, without median impunctate line. Supraclypeal area and face above antennal fossae as in carlini. Vertex above lateral ocellus equals slightly less than two ocellar diameters, surface dulled by punctures and dense tessellation. Genal area in profile equal to one and one-half to one and three-fourths eye width, surface with fine sparse punctures and reticular shagreening.
Thoracic form and sculpturing as in carlini. Wing venation as in carlini but second submarginal cell much narrower along anterior margin than along posterior margin.
Metasomal terga and sterna sculptured as in carlini but usually slightly duller. Tergum 7 without distinct pygidial area. Sternum 6 with apical margin straight across, not produced, without raised internal triangular area.
Terminalia as in figures 49-53; much as in transnigra but sternum 8 with apicomedian emargination shallow.
VESTITURE. — In general pale ochraceous to white except as follows: head often with brown hairs on vertex, face below ocelli and along inner margins of eyes and genal area near eye margin (often entirely pale); terga 3-5 or 2-5 with some brown hairs at extreme bases or mostly brown; hind tibiae and basitarsi with posterior surfaces with brown hairs. Terga without apical fasciae; sternum 6 with subapical hairs short, directed posteriorly; thoracic hairs not especially short.
Reprinted with permission from: Mitchell, T.B. 1960. Bees of the Eastern United States. North Carolina Agricultural Experiment Station Technical Bulletin No. 141.
FEMALE. — Length 11 mm.; clypeus broadly convex, projecting about one-half below suborbital line, smooth but rather dull, punctures fine, rather sparse medially, becoming quite close at extreme sides; facial foveae broad above, occupying most of area between eyes and lateral ocelli, covered with fuscous tomentum; space between margin of vertex and lateral ocelli very slightly less than distance between them; cheeks broader than eyes, rounded posteriorly, dull, punctures very minute and rather sparse; length of malar space about one-third basal width of mandibles; basal segment of flagellum subequal to 2nd and 3rd combined; process of labrum rather large, broadly subtriangular, apex quite broadly truncate; pubescence pale ochraceous on lower part of face and cheeks, becoming fuscous above antennae, on vertex and on cheeks above; thoracic integument dull and tessellate, punctures of scutum shallow, rather fine and close but obscure, those on scutellum quite close and fine beneath the dense pubescence; punctures of pleura minute and obscure, rather close; enclosure of propodeum dull and tessellate; pubescence of scutum, scutellum and propodeum pale ochraceous, that on pleura and legs blackish except for considerably pale ochraceous pubescence on front and hind femora; propodeal corbicula well developed, with a distinct anterior fringe, pale ochraceous; trochanteral floccus well developed, fuscous: tibial scopa dense, hairs elongate, simple, black; all basitarsi slightly narrower than their respective tibiae; 2nd submarginal cell slightly shorter than 3rd, receiving 1st recurrent at middle; abdominal terga smooth, somewhat shining, apical depressed area rather shallow, equaling medially slightly over one-third length of disc, nearly impunctate, basal portions of disc very finely and quite closely punctate, distal pubescence very short, thin, suberect, fuscous even on basal segment, tergum 5 with a dense, apical, fuscous fimbria, fasciae not developed.
MALE. — Length 10 mm.; clypeus very slightly convex, projecting about one-third below suborbital line, rather smooth, finely, regularly and rather closely punctate; space between margin of vertex and lateral ocelli subequal to distance between them; cheeks considerably broader than eyes, rounded posteriorly (as in acra, fig. 21), rather dull, punctures minute; malar space quite short; basal segment of flagellum slightly longer than 2nd, subequal in length to 3rd and following segments; process of labrum rather large, obscurely subtriangular, apex rather narrowly truncate and very slightly emarginate; mandibles slender, very slightly curved, with a distinct subapical inner tooth, overlapping about one-fourth; pubescence of head and thorax whitish, faintly yellowish above, sometimes with some fuscous hairs along inner margins of eyes; thoracic integument dull and tessellate, punctures of scutum rather obscure, rather fine and close anteriorly, more sparse posteriorly, those on scutellum very fine, irregular, rather sparse; pleura more densely tessellate, punctures very obscure; enclosure of propodeum dull and tessellate, obscurely substriate along basal margin; legs entirely pale pubescent, all basitarsi slender and elongate. considerably narrower than their respective tibiae; 2nd submarginal cell slightly shorter than 3rd, receiving 1st recurrent slightly basad of middle; abdominal terga somewhat shining, apical depressed areas distinct laterally, rather obscure medially where they occupy about one-third length of disc, becoming reddish-hyaline toward rims, nearly impunctate, basal portions of discs quite closely and finely punctate, pubescence short, suberect, thin and obscure, entirely pale, fasciae not developed; apical portion of sternum 8 quite broad, with a median ventral ridge beyond which it is densely pubescent to the more narrowly truncate tip; penis valves quite broadly expanded but not excavated, gonocoxites robust, slightly dilated apically, gonocoxal lobes strongly produced, subtriangular.
DISTRIBUTION. — Transcanadian, from British Columbia to Nova Scotia, and in the eastern United States, from Minnesota to the New England states, south to Georgia; April to July.
FLOWER RECORDS. — Brassica and Vaccinium. This also is recorded by Brittain and Newton (1934) on Aster, Pyrus malus, Rubus and Syringa.