Reprinted with permission of the American Entomological Society from:
LaBerge, W. E., Bouseman, J. K. 1970. A revision of the bees of the genus Andrena of the Western Hemisphere. Part III. Tylandrena. Transactions of the American Entomological Society 96: 543-605.
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This is a large, widespread, vernal bee but is known to be abundant in only a few localities. It has been confused with a superficially very similar bee in the subgenus Melandrena which remains unnamed. A. perplexa can be readily distinguished from erythrogaster by the form of the labral process, the pronotal humeral angles and the more punctate terga, as described below. The female of perplexa is further distinguished by the broad pygidial plate with a rounded apex and the male by the relatively short first flagellar segment.
FEMALE. MEASUREMENTS AND RATIOS. — N = 20; length, 12-15 mm; width, 3-4 mm; wing length, M = 5.14 ± 0.251 mm; FL/FW, M = 0.91 ± 0.004; FOVL/FOVW, M = 3.31 ± 0.044.
INTEGUMENTAL COLOR. — Generally black except as follows: mandible with apical third to half rufescent; flagellar segments 2-10 dark brown below; wing veins and pterostigma dark reddish-brown to brownish-black, membrane only moderately infumate, smoky-brown especially apically; distitarsi rufescent.
STRUCTURE. — Antennal scape length equals first three and one-half flagellar segments or slightly more; flagellar segment 1 slightly shorter than segments 2 plus 3 (about as 9:10), 2 slightly shorter than 3, 3 slightly shorter than 4. Eyes each about four times as long as broad, inner margins slightly diverging towards mandibles. Malar space short, six or seven times as broad as minimum length. Mandible in repose extends about one-fourth its length beyond middle of labrum (unless worn). Galea dulled by fine regular tessellation, lateral portion about one-third as broad as dorsal. Maxillary palpus as in erythrogaster but segmental ratio about 1.0:1.1 :0.9 :0.8:0.7:0.7. Labial palpus as in erythrogaster but ratio about 1.0:0.6:0.6:0.4. Labral process about three times as wide at base as median length, slightly thickened apically; labrum below process with three prominent cristae, a median and two lateral, forming two concave, shiny depressions, rarely with a single weak crista in each depression and usually with several very weak aristae laterally. Clypeus rather rounded, with a prominent median, longitudinal, shiny, impunctate ridge in apical half (rarely this extends to posterior margin but posterior half of ridge usually obscured by punctures and/or coarse shagreening); punctures small, round, separated by less than half a puncture width, somewhat irregular in size, surface dulled by coarse reticular shagreening in posterior third to half. Supraclypeal area dulled by minute crowded punctures. Genal area almost twice width of eye in profile, with minute punctures separated mostly by one to two puncture widths, surface dulled by reticular shagreening. Vertex above lateral ocellus equals at least one and one-half ocellar diameters, dulled by coarse tessellation and crowded punctures (especially above ocelli). Face above antennal fossae with close-set, weak, longitudinal rugulae, surface dulled by punctures and coarse tessellation. Facial fovea separated from lateral ocellus by less than one ocellar diameter.
Pronotum with humeral angle above diagonal suture somewhat depressed posteriorly forming an ear-shaped lobe. Mesoscutum with small round punctures separated by one puncture width or slightly more except sparser posteromedially, surface dulled by regular tessellation even on bottoms of punctures. Scutellum similar but shinier, tessellation usually finer. Metanotum and propodeum as in erythrogaster but dorsal enclosure of propodeum usually granularly sculptured in basal half. Mesepisterna with small shallow punctures separated by half to two puncture widths (more posteriorly), surface and bottoms of punctures dulled by fine regular tessellation. Wing veins as in erythrogaster but second submarginal cell usually much longer, along posterior margin almost as long as third cell and along anterior margin twice as long as third cell. Tergum 1 with apical area impunctate, basal area with small punctures separated by one to four puncture widths (mostly two to three), surface shiny to moderately shiny, with fine reticular shagreening. Terga 2 and 3 with apical areas largely impunctate but with scattered minute punctures in basal half to third, surface dulled or moderately dulled by regular tessellation; basal areas with small distinct punctures separated mostly by half to one puncture width, surface shiny, finely reticularly shagreened, if at all. Pygidial plate broad with broad round apex, internal area not markedly raised, with distinct close-set punctures (unless worn). Sterna as in erythrogaster but duller, more shagreened especially apical two sterna.
VESTITURE. — Generally ochraceous, darker on vertex and thoracic dorsum (occasionally dull fox-red); terga without trace of fasciae; sternal subapical fimbriae weak. Pollen-collecting hairs as in erythrogaster except as follows: anterior corbicular hairs shorter; generally ochraceous. Hairs on and below tibial plates brown; distitarsi with outer surface often reddish-brown, inner surfaces orange to reddish-brown.
MALE. MEASUREMENTS AND RATIOS. — N = 20; length, 9-14 mm; width, 2.5-4.0 mm; wing length, M = 4.48 ± 0.242 mm; FL/FW, M = 0.90 ± 0.010; FS1/FS2, M = 1.23 ± 0.017.
INTEGUMENTAL COLOR. — Generally as in female but wing membrane less infumate, basitarsi often slightly rufescent and terga with apical areas often slightly hyaline, translucent brown.
STRUCTURE. — Antennae of moderate length, in repose barely reaching beyond posterior margins tegulae; scape length about equal to two and one-half flagellar segments; flagellar segment 2 slightly shorter than segment 3, segments 1-11 longer than broad, 3-10 subequal in length to each other. Eyes each three and one-third to three and one-half times as long as broad, inner margins slightly diverging toward mandibles. Malar space mandible and galea as in female but mandible somewhat longer, moderately decussate. Maxillary palpus as in female but segmental ratio about 0.7:1.0:0.8:0.8;0.7:0.6. Labial palpus as in female but ratio about 1.0:0.7:0.5:0.5. Labral process less than twice as broad at base as long, narrow, weakly emarginate, lateral margins raised so that median longitudinal depression exists, shiny; cristae absent. Clypeus rounded, entire, surface dulled by somewhat irregular, deep punctures separated by half a puncture width or less and fine tessellation. Genal area and face as in female but facial rugulae much more irregular. Vertex as in female. Thoracic sculpturing as in female but mesoscutum and scutellum often slightly shinier medially and lateral surface propodeum more punctate and tessellate. Wing venation as in female. Tergum 1 as in female. Terga 2-3 as in female but apical areas usually less punctate basally and basal areas usually with punctures separated mostly by two puncture widths, basal areas usually shiny, weakly shagreened. Terga 4-6 similar to 3 but progressively more sparsely punctate and duller. Sterna as in erythrogaster but last exposed sternum (sixth) with extremely shallow, longitudinal sulcus always present, surface dulled, finely tessellate.
Terminalia as figured (Figs. 16-20). Note the following: gonocoxite with median dorsal lobe elongate, apical process with few hairs; sternum 7 feebly emarginate medially; sternum 8 with apical part set off abruptly from basal part, with abundant long slender hairs.
VESTITURE. — Generally as in female but lacking pollen-collecting hairs and without brown or reddish-brown hairs on legs; sterna 2-5 with subapical fimbriae weak, sternum 6 with subapical fimbria well-formed and usually hiding margin of sternum but of shorter hairs than on preceding sterna.
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 13 mm.; clypeus broadly convex, projecting about one-half below suborbital line, shining, rather closely and deeply punctate, with a narrow median impunctate line; facial foveae broad above, occupying most of space between eyes and ocelli, covered with pale ochraceous tomentum; space between margin of vertex and lateral ocelli slightly shorter than distance between ocelli; cheeks slightly broader than eyes, smooth, minutely punctate, rounded posteriorly; malar space very short; basal segment of flagellum subequal to 2nd and 3rd combined; process of labrum rather large, subtriangular, broadly truncate apically; mandibles of moderate length, with a distinct, inner, subapical tooth; pubescence of head, thorax, legs and base of abdomen entirely pale ochraceous, becoming more whitish below, slightly infuscated on front and middle basitarsi; scutum closely and finely punctate anteriorly, punctures becoming somewhat more sparse posteriorly where surface is more shining; scutellum somewhat shining, punctures rather irregular, fine and rather sparse; integument of pleura and propodeum dull and tessellate, punctures obscure; enclosure of propodeum smooth, tessellate; propodeal corbicula dense but rather short, with a distinct anterior fringe, pale ochraceous; trochanteral floccus well developed, whitish; tibial scopa short, dense and white, of simple hairs; all basitarsi slightly narrower than their respective tibiae; 2nd submarginal cell about as long as 3rd, receiving 1st recurrent near middle; abdominal terga somewhat shining, apical depressed areas occupying about one-third the median length of discs, nearly impunctate, basal portions of discs closely and finely punctate, punctures on basal tergum more sparse, as well as those on tergum 4 which is relatively dull, pubescence very short and thin, entirely pale, fasciae not developed.
MALE. — Length 11 mm.; length and breadth of face subequal; clypeus broad and rather short, projecting but little below suborbital line, somewhat convex medially, surface dull, densely and very finely punctate beneath the dense, long pubescence; space between margin of vertex and lateral ocelli slightly shorter than space between ocelli; cheeks broad and flat, posterior margin more rounded than angulate, surface dull, very minutely and obscurely punctate; malar space very short; basal segments of flagellum subequal to 2nd segment; process of labrum subquadrate, nearly as long as broad, apex very slightly incurved; mandibles narrow and elongate, slightly curved, with a fine but distinct inner subapical tooth, overlapping fully one-third; pubescence of head and dorsum of thorax pale fulvous, more whitish on cheeks, pleura, propodeum, legs and base of abdomen; thoracic integument rather dull, scutum closely and finely punctuate anteriorly, punctures becoming more sparse posteriorly and on scutellum, those on pleura shallow and obscure; enclosure of propodeum relatively smooth but dull and tessellate; all basitarsi slender and elongate, considerably narrower than their respective tibiae; 2nd submarginal cell about as long as 3rd, receiving 1st recurrent near middle; abdominal terga somewhat shining, apical depressed areas equaling about one-fourth the median length of discs, nearly impunctate, basal portion of discs finely but rather deeply and closely punctate, punctures sparse on basal tergum and on tergum 4 which is relatively dull, pubescence very short and obscure, entirely pale, fasciae entirely lacking; apical portion of sternum 8 with a submedian ventral protuberance, densely pubescent from this to the apex which is rather broad, truncate and slightly incurved apically; penis valves somewhat expanded basally, not excavated, gonocoxites considerably dilated apically, gonocoxal lobes strongly produced, narrowly rounded.
DISTRIBUTION. — Minnesota, Michigan and New York, south to Texas, Georgia and North Carolina; March, April and May.
FLOWER RECORDS. — Amelanchier, Aronia, Crataegus, Fragaria, Geranium, Malus, Melilotus, Prunus, Pyracantha, Pyrus, Rubus, Salix, Senecio and Viburnum.
Described using the synonymous name: Andrena viburnella Graenicher
FEMALE. — Length 13 mm.; clypeus projecting nearly one-half below suborbital line, broadly convex, with a narrow and indistinct, median, impunctate line, otherwise rather closely and deeply punctate; facial foveae broad above, occupying most of area between eyes and lateral ocelli, covered with pale ochraceous tomentum; space between margin of vertex and lateral ocelli slightly less than distance between them; cheeks slightly broader than eyes, rounded posteriorly, rather dull, very minutely and obscurely punctate; malar space extremely short; basal segment of flagellum subequal to 2nd and 3rd combined; process of labrum quite large, subtriangular, apex somewhat rounded; pubescence of head and thorax entirely pale, whitish below, becoming very pale ochraceous above; thoracic integument rather dull; punctures of scutum rather coarse and indistinct but shallow, quite close anteriorly, becoming somewhat more sparse posteriorly, finer and very sparse on each side of scutellum which has a median, densely punctate line, those on pleura extremely minute and obscure; enclosure of propodeum dull, tessellate, very finely subrugose along basal margin; propodeal corbicula rather short but well developed, with a rather poorly developed anterior fringe; trochanteral floccus well developed, tibial scopa rather dense, hairs simple, rather elongate, entirely white; all basitarsi slightly narrower than their respective tibiae, pubescence of legs in general whitish; 2nd submarginal cell very slightly shorter than 3rd, receiving 1st recurrent near middle; abdominal terga shining, obscurely violaceous, apical margins rather broadly depressed, depressed areas occupying about one-third median length of discs, largely impunctate, with remainder of discs, in marked contrast, very finely, closely and deeply punctate, punctures of basal terga slightly more separated, discal pubescence extremely short, suberect, entirely pale, fasciae not developed.
MALE. — Length 10 mm.; clypeus broad and rather flat, projecting but very little below suborbital line, dull, closely and finely punctate beneath the dense white pubescence; space between margin of vertex and lateral ocelli very slightly less than distance between ocelli; cheeks slightly broader than eyes, rounded posteriorly (as in acra, fig. 21), rather dull, punctures very minute and obscure; malar space very short; basal segment of flagellum hardly 6 0 longer than 2nd, somewhat shorter than 3rd and following segments; process of labrum quite large, subtriangular, tip narrowly truncate; mandibles rather slender and elongate, with a distinct, inner, subapical tooth, slightly curved, without a basal inferior projection; pubescence of entire body pale, largely whitish, faintly creamy above, rather long and copious on head and thorax; thoracic integument dull, tessellate, punctures of scutum well separated, shallow but rather coarse and distinct, those on scutellum finer and sparse, those on pleura very obscure; enclosure of propodeum dull, tessellate, obscurely striate toward basal margin; all basitarsi slender and elongate, considerably narrower than their respective tibiae; 2nd submarginal cell slightly shorter than 3rd, receiving 1st recurrent near middle; abdominal terga smooth, shining, faintly violaceous, rather narrowly and slightly depressed apically, depressed areas impunctate, discs otherwise with deep, distinct and rather close punctures, discal pubescence extremely short, suberect, entirely pale, fasciae not developed; apical portion of sternum 8 with a very pronounced, submedian, ventral protuberance which is subcarinate, with dense pubescence from here to the narrowed, subtruncate tip; penis valves slightly expanded basally, not excavated, gonocoxites quite broadly expanded apically, gonocoxal lobes somewhat produced, subtriangular.
DISTRIBUTION. — Oregon to Connecticut, south to Texas, Mississippi and Georgia; March to June.
FLOWER RECORDS. — Acer, Amelanchier, Aronia, Brassica, Crataegus, Fragaria, Malus, Padus, Prunus, Pyrus, Ranunculus, Rubus, Salix and Viburnum.