Reprinted with permission of the American Entomological Society from:
LaBerge, W. E. 1973. A revision of the bees of the genus Andrena of the Western Hemisphere. Part VI. Subgenus Trachandrena. Transactions of the American Entomological Society 99: 235-371.
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This unusual eastern species belongs in the spiraeana-heraclei group of species but is not closely related to any of them. The female of rehni can be easily recognized by the facial foveae which are extremely shallow and have a very broad lower portion. In this character females approach the more primitive condition found in the subgenus Scrapteropsis. The male of rehni can be easily recognized by the form of the sixth sternum which is sharply bent downwards at about two-fifths distance from apex (the apicomedian area appears to be produced).
FEMALE. MEASUREMENTS AND RATIOS. — N = 20; length, 8-10 mm; width, 2.5-3.0 mm; wing length, M = 3.24 ± 0.112 mm; FL/FW, M = 1.01 ± 0.005; FOVL/FOVW, M = 3.26 ± 0.045.
INTEGUMENTAL COLOR. — Black except as follows: mandible with apical half rufescent; flagellar segments 2-10 red below (occasionally apical 4 or 5 segments yellow); tegulae translucent red; wing membranes hyaline, slightly milky or yellowed, veins and pterostigma dark red; terga 1-4 with apical rims hyaline as in heraclei; sterna and tarsi dark rufescent.
STRUCTURE. — Antennae as in sigmundi. Eyes each about four times as long as broad, inner margins parallel or converging slightly towards vertex. Malar space, mandible and galea as in sigmundi. Maxillary palpus as in sigmundi but segmental ratio about as 1.0:0.8:0.6:0.6:0.4:0.5. Labial palpus as in sigmundi but ratio about as 1.0:0.7:0.5:0.3. Labral process trapezoidal or squarish; labrum below process dull, not sulcate, with or without several weak cristae. Clypeus with round punctures separated by half a puncture width or slightly more in posterior half, becoming sparser anteromedially, without distinct median impunctate line; surface shiny, Supraclypeal area with minute punctures separated by more than half a puncture width, surface shiny, unshagreened. Genal area broader than eye in profile, with regular round punctures separated by half to one puncture width (slightly more medially); surface shiny, unshagreened or delicately so, without rugulae; ventrally with distinct rugae converging towards mandibles and distinct punctures. Vertex above lateral ocellus equals distinctly more than one ocellar diameter, with two or three, irregular rows of distinct punctures and fine tessellation moderately dulling surface. Face above antennal fossae distinctly and densely punctate, shagreening delicate or absent. Facial fovea extremely shallow, separated from lateral ocellus by one-half to three-fourths of an ocellar diameter; lower portion broad, broader than half of upper area and usually broader than greatest space between eye margin and fovea.
Sculpturing of thorax as in spiraeana except as follows: scutellar punctures distinctly larger than mesoscutal; propodeal dorsal enclosure with rugae irregular; mesepisternum with large punctures with narrow rounded ridges between punctures (not sharply punctatorugose), surface finely but distinctly reticularly shagreened. Tibial spurs normal. Wing venation and pterostigma as in sigmundi.
Metasomal tergum 1 with apical area indistinct but medially almost half as long as tergum; basal area punctures sparse; apical area punctures separated by one puncture width or more except in impunctate hyaline rim; surface shiny, unshagreened. Terga 2-4 similar to 1 but apical areas more distinctly impressed and equal fully to half tergal length medially. Pygidial plate V-shaped with rounded apex and distinct raised internal triangular area. Sterna densely punctate except at extreme bases and in narrow apical areas; surfaces dulled by reticulotransverse shagreening.
VESTITURE. — Generally white to pale ochraceous and as in sigmundi except as follows: facial hairs, especially surrounding antennal fossae, highly plumose, fuzzy; tergum 2 with apical pale fascia broadly interrupted medially, tergum 3 with fascia narrowly interrupted or complete and thinned medially; terga 5 and 6 and inner surfaces tarsi yellow.
MALE. MEASUREMENTS AND RATIOS. — N = 20; length, 7-10 mm; width, 2.0-2.5 mm; wing length, M = 3.01 ± 0.092 mm; FL/FW, M = 1.08 ± 0.008; FS1/FS2, M = 0.59 ± 0.008.
INTEGUMENTAL COLOR. — Black with same exceptions as in female but flagellar segments 2-11 usually dark reddish-brown below; terga 1-5 usually more broadly hyaline apically.
STRUCTURE. — Antennae in repose barely reaching propodeum; scape length equals first two flagellar segments or extremely slightly more; flagellar segments as in forbesii; surface dull as in sigmundi. Eyes each about three and one-fourth times as long as broad, inner margins parallel or converging slightly towards mandibles. Malar space, mandible and galea as in female. Maxillary palpus as in sigmundi but segmental ratio about as 1.0:0.9:0.8:0.6:0.4:0.4. Labial palpus as in sigmundi but ratio about as 1.0:0.7:0.4:0.4. Labrum as in sigmundi. Clypeus as in female but often more regularly punctate, without apicomedian area of sparser punctures. Supraclypeal area and genal area as in female. Face above antennal fossae as in female but punctures less distinct, obscured by fine shagreening and fine longitudinal rugulae (at least laterally). Vertex as in female.
Thorax sculptured as in spiraeana except as follows: mesoscutum peripherally with light reticular shagreening; propodeal dorsal enclosure irregularly rugose. Tibial spurs normal. Venation and pterostigma as in sigmundi.
Terga 1-5 sculptured as in female terga 1-4 but apical areas slightly shorter than half median tergal length and apical area punctures usually as sparse or almost as sparse as in basal area of each tergum. Sterna 2-5 with apical margins impunctate, basally with small round punctures relatively regularly spaced by two to three puncture widths or more. Sternum 5 apically obtusely produced and bent downwards almost or quite at right angle to base of sternum. Terminalia as in sigmundi; see figures 60-63. Note the elongated lateral arms of the gonocoxites and the less bent penis valves.
VESTITURE. — Generally white to pale ochraceous and distributed as in spiraeana but tergal apical pale bands denser, less silky, and facial hairs, especially surrounding antennal fossae, highly plumose as in female.
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 8 mm.; clypeus slightly convex, projecting about one-third below suborbital line, shining between deep, distinct, rather coarse and close punctures, these slightly separated in center apically; facial foveae rather broad, occupying above most of space between eyes and ocelli, only slightly narrowed below, covered with whitish-ochraceous tomentum; space between margin of vertex and lateral ocelli subequal to distance between ocelli; cheeks very slightly broader than eyes, rounded posteriorly, rather dull, closely and deeply, but rather finely punctate, punctures becoming quite sparse above on lateral portions of vertex; malar space very short; basal segment of flagellum slightly shorter than 2nd and 3rd combined; process of labrum quite large, considerably broader than long, slightly narrowed to the broadly truncate, apical margin; pubescence of head, thorax and legs whitish, faintly tinged with yellowish above and on the more apical portions of legs; scutum somewhat shining, rather deeply and sparsely punctate, punctures somewhat closer at anterior, lateral angles, becoming quite sparse near center of disc, moderately coarse, those on scutellum somewhat more coarse, more scattered and irregular, surface more shining; pleura dull, shallowly and rather obscurely rugose anteriorly, becoming relatively smooth, with fine punctures posteriorly; dorsal area of propodeum oblique, triangle coarsely rugoso-striate; propodeal corbicula short, rather poorly developed, without a distinct anterior fringe, whitish-ochraceous; trochanteral floccus rather poorly developed, thin but rather elongate, whitish; hind tibiae somewhat broadened apically, the apex not quite twice width of basitarsi, scopa rather dense, hairs of moderate length, simple, largely whitish, becoming somewhat yellowish toward base posteriorly; fore and mid basitarsi slightly narrower than their respective tibiae; 2nd submarginal cell considerably shorter than 3rd, receiving 1st recurrent slightly beyond middle; abdominal terga somewhat shining, very finely, but deeply and distinctly punctate, punctures well separated but not sparse, apical impressed areas quite distinct, occupying medially fully half length of disc, quite strongly narrowed laterally, becoming yellowish-hyaline along rims, discal pubescence very short, thin, erect, entirely pale, terga 2-4 with thin, white, apical fasciae, that on tergum 2 widely interrupted, that on 3 more narrowly so, tergum 5 with a brownish, apical fimbria.
MALE. — Length 8 mm.; clypeus convex, projecting but very slightly below suborbital line, quite closely, deeply and rather coarsely punctate, surface between punctures shining, quite densely pubescent; space between margin of vertex and lateral ocelli slightly shorter than distance between them; cheeks very slightly broader than eyes, rounded posteriorly, somewhat shining, the punctures minute, rather close but obscure, becoming quite sparse on vertex laterally; malar space very short; basal segment of flagellum not much longer than its apical width, considerably shorter than 2nd and following segments; process of labrum rather short, quite broad, broadly truncate apically; mandibles with a distinct, inner, subapical tooth, overlapping not more than one-fourth; pubescence of head, thorax and legs entirely pale ochraceous; scutum somewhat shining, punctures deep, distinct, rather coarse, well separated but not sparse anteriorly, becoming rather close toward sides and slightly more widely separated posteriorly, those of scutellum very much coarser, close and deep, almost crowded; pleura coarsely rugose; dorsal area of propodeum nearly horizontal, triangle very coarsely striate; all basitarsi slender and elongate, considerably narrower than their respective tibiae; 2nd submarginal cell considerably shorter than 3rd, receiving 1st recurrent slightly beyond middle; abdominal terga smooth, shining, very finely and rather closely punctate, apical impressed areas rather broad, occupying medially nearly one-half length of disc, quite shallow, becoming narrowly yellowish-hyaline along rims, discal pubescence very obscure, short, thin, sparse, entirely pale, terga 2-4 subfasciate apically toward sides, the fasciae whitish and rather obscure; basal portion of sternum 8 angulate laterally, apical portion constricted, rather slender, quite strongly protuberant beneath medially, the apex rounded, apical portion quite densely pubescent; penis valves slender apically, slightly broadened toward base, the sides narrowly grooved, gonocoxites strongly dilated apically, the resulting lobes much longer than broad, gonocoxal lobes slightly produced, but very short, acute apically.
DISTRIBUTION. — The New England states, south to North Carolina and Georgia; May, June and July.
FLOWER RECORDS. — Aruncus, Castanea, Ceanothus, Chrysanthemum and Hydrangea.
Described using the synonymous name: Andrena votula Mitchell
FEMALE. — Length 10 mm.; face slightly longer than distance between eyes; eyes about parallel; foveae constricted below, but not very abruptly so, with very little space between this part and eye margin; lateral ocelli separated from hind margin of vertex by a space somewhat greater than their diameter; cheeks very slightly broader than eyes; clypeus protruding but slightly below suborbital line, shining between deep, distinct and rather coarse and close punctures, these quite uniformly distributed; face below ocelli somewhat shining between deep, distinct and rather close punctures, those on vertex quite coarse and deep, close medially, becoming quite sparse toward each side, those on cheeks becoming very fine and close; malar space hardly evident; process of labrum broadly subtriangular, with truncate apex, about half as long as basal width; basal segment of flagellum slightly shorter than 2nd and 3rd combined, median segments about as long as broad; pubescence of head and thorax entirely pale yellowish, becoming somewhat more whitish below, rather dense between antennae and eyes, cheeks below, and on thorax laterally; scutum and scutellum somewhat shining, punctures of scutum quite coarse, deep and distinct, well separated even anteriorly, but not sparse even posteriorly, those on scutellum considerably more coarse and close, this plate almost rugose; pleura coarsely rugoso-punctate; dorsal area of propodeum coarsely striate, lateral areas more finely rugose; propodeal corbicula rather dense but short, with a few inner hairs but no anterior fringe; trochanteral floccus quite short; legs dark in general, the more apical segments becoming somewhat reddened, basitarsi quite slender, hind tibiae somewhat broadened apically, tibial scopa yellowish and of rather elongate, dense hairs, spurs pale yellowish; wings sub-hyaline, veins pale testaceous, stigma more ferruginous, 2nd submarginal cell about half length of 3rd, receiving 1st recurrent near middle; tegulae dark anteriorly, more reddish-hyaline posteriorly, yellowish along outer margin; abdominal terga smooth but rather dull, segment 2 impressed for half its median length, 3 and 4 somewhat less so, punctures quite uniform, very fine and rather close but distinctly separated, impressed areas of segments 3 and 4 somewhat reddened, segments 2-4 with rather dense, whitish, apical fasciae, widely interrupted on 2, slightly so on 3, apical fimbria golden brown.
TYPES. — Holotype: Female, Milwaukee, Wisconsin, May 30, 1902 [U.S.N.M.] Paratype: 1 F (stylopized), Ann Arbor, Michigan, May 23, 1901 [Hubbell].