Reprinted with permission of the American Entomological Society from:
LaBerge, W. E. 1980. A revision of the bees of the genus Andrena of the Western Hemisphere. Part X. Subgenus Andrena. Transactions of the American Entomological Society 106: 395-526.
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This moderate-sized, widely spread species is relatively rare in collections; The female of A. rufosignata resembles that of mandibularis or the pale specimens of thaspii in vestitural color. However, the female of rufosignata has the basal inferior mandibular teeth either present, or absent, the labral process bidentate as in thaspii but narrower, the metasomal terga lacking apical pale fasciae as in mandibularis, and the clypeus more vaulted and longer than either mandibularis or thaspii; Both sexes of rufosignata have the malar space slightly longer than usual; The male of rufosignata has basal mandibular teeth as in mandibularis, a bidentate labral process as in thaspii, lacks tergal pale fasciae, has the sixth sternum relatively flat (not apically reflexed), and sterna 2-5 have short weak subapical fimbriae.
FEMALE. MEASUREMENTS AND RATIOS. — N = 20; length, 9-11 mm; width, 2.5-3.5 mm; wing length; M = 3.78 ± 0.195 mm; FL/FW, M = 0.99 ± 0.007; FOVL/ FOVW, m = 2.87 ± 0.029.
INTEGUMENTAL COLOR. — Black except as follows: mandible with apical third or less rufescent; flagellum below reddish-brown to brown; tegula reddish-brown; wing membranes hyaline, slightly infumate, veins reddish-brown to brown; tibial spurs testaceous; distitarsi dark rufescent; terga 2-5 with apical areas slightly translucent, often dark rufescent; sterna 2-5 with apical areas hyaline, colorless, basal areas usually with rufescent reflections.
STRUCTURE. — Antennal scape length equals first three and one-fourth flagellar segments or slightly more; flagellar segment 1 as long as next two segments or slightly longer, segment 2 shorter than 3 and about as long as broad; Eyes each about three and three-fourths times as long as broad, inner margins parallel; Mandible as in frigida but usually with small inferior angle or tooth basally (absent in about a third of specimens); Malar space long, one-third times as long as width of mandibular base or almost; Galea as in frigida; Maxillary palpus as in frigida but segmental ratio about as 0.9:1.0:0.9:0.9:0.9:0.7; Labial palpus as in frigida but ratio about as 1.0:0.7:0.6:0.6; Labral process moderate in size, trapezoidal with apical half usually constricted laterally, apical margin emarginate; labrum below process with weak median crista, not sulcate; Clypeus strongly vaulted, long, with moderately coarse, relatively sparse punctures separated mostly by half to one puncture width or more, often with an irregular median impunctate line and/or small impunctate apicomedian area; surface shiny apicomedially to shagreened at base; Supraclypeal area as in frigida; Face above antennal fossae dulled by coarse longitudinal rugulae and distinct interrugal punctures, punctures especially abundant in triangular area just below ocelli; Facial fovea large, shallow, extending below to beyond level of lower margins antennal fossae, separated from lateral ocellus by half an ocellar diameter or slightly more; Vertex above lateral ocellus equals one ocellar diameter or slightly less, opaque, tessellate; Genal area moderately broad, in profile equal to about one and one-fourth times width of eye; surface dulled by fine reticular shagreening and minute sparse punctures (not crowded near eye margin).
Pronotum and mesoscutum as in frigida; Scutellum shagreened, sparsely punctate, occasionally moderately shiny; Propodeum sculptured as in mandibularis but dorsal enclosure often slightly depressed along midline and often shiny to moderately shiny near lateral margins and apically; posterior surface with punctures obscure.
Metasomal terga 1-4 sculptured as in frigida but apical areas shinier; Pygidial plate V-shaped with rounded apex (unless worn) but not as broad and blunt as in mandibularis, with distinct raised internal triangular area; Sterna 2-5 sculptured as in frigida.
VESTITURE. — As in mandibularis but in western specimens tibial scopal hairs washed with fuscous posteriorly, dorsal thoracic hairs usually pale ochraceous and facial fovea usually with pale brown to brown hairs at least in upper half; Form and distribution of hairs as in mandibularis.
MALE. MEASUREMENTS AND RATIOS. — N = 20; length, 7-10 mm; width, 1.5-2.5 mm; wing length, M = 3.26 ± 0.166 mm; FL/FW, M = 0.99 ± 0.008; FS1/FS2, M = 1.03 ± 0.023.
INTEGUMENTAL COLOR. — As in female.
STRUCTURE. — Antennae as in mandibularis; Eyes each about three times as long as broad or slightly longer, inner margins parallel; Mandible as in mandibularis; Malar space as in female but often slightly shorter; Galea as in female; Maxillary palpus as in female but segmental ratio about as 0.9:1.0:1.0:1.0:0.9:0.9; Labial palpus as in female but ratio about as 1.0:0.8:0.8:0.8; Labral process small, shiny, strongly reflexed, bidentate apically; labrum apical to process shiny, flat, often with weak median crista; Clypeus flattened, long, with small sparse punctures separated mostly by one to two puncture widths or more, median impunctate line absent or weak; surface shiny, unshagreened except in basal half or less; Supraclypeal area, face above antennal fossae and vertex as in female; Genal area broad, angulate posteriorly, in profile about one and one-third times as broad as eye, surface slightly dulled by minute sparse punctures and fine shagreening.
Pronotum as in mandibularis; Mesoscutum and scutellum as in female; Propodeum as in female but lateral surfaces more coarsely tessellate.
Metasomal terga sculptured as in female; Tergum 7 without pygidial-like area; Sterna 2-5 sculptured as in frigida; Sternum 6 flat, as in mandibularis.
Terminalia as in figures 82-86.
VESTITURE. — White to pale ochraceous except dorsum of thorax often ochraceous, inner surfaces hind tarsi pale yellow, and face with dark hairs near inner margins compound eyes; Form and distribution of vestiture as in mandibularis except sterna 2-5 with subapical pale fimbriae weak, composed of hairs shorter than apical area of each sternum.
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 9 mm.; face slightly longer than broad; clypeus convex, produced considerably below suborbital line, surface smooth, sparsely and finely punctate medially, becoming somewhat more closely punctate laterally; facial foveae broad above, about filling area between eyes and lateral ocelli, covered with ochraceous tomentum, sometimes appearing fuscous at certain angles; space between margin of vertex and lateral ocelli less than their diameter; cheeks very slightly broader than eyes, smooth but rather dull, very finely punctate; malar space well developed, nearly half as long as basal width of mandible; basal segment of flagellum subequal to 2nd and 3rd combined; process of labrum subtriangular, tip very narrowly truncate; mandibles of ordinary length, with a distinct, subapical, inner tooth; pubescence of head, thorax, and base of abdomen entirely pale, somewhat ochraceous above, whitish below; thoracic integument dull, tessellate; scutum and scutellum with scattered, shallow and rather obscure punctures; enclosure of propodeum smooth; propodeal corbicula rather short, with a distinct anterior fringe; trochanteral floccus well developed; tibial scopa long, dense, of simple hairs; hind tibiae narrow and elongate, the basitarsi slightly narrower; mid basitarsi only slightly narrower than their tibiae; 2nd submarginal cell shorter than 3rd, receiving 1st recurrent near apex; abdominal terga smooth, dull, nearly impunctate except for some very fine, obscure punctures toward base, apical margins somewhat depressed, the depressed areas somewhat reddened, discal pubescence entirely pale, short, fasciae not developed.
DISTRIBUTION — Minnesota to New Brunswick and New England; May and June.
Lanham (1949) placed rufosignata in the subgenus Andrena, but it seems to the writer that it might better be placed in Conandrena. The facial quadrangle is not as distinctly elongate as in bradleyi or carolina, but it bears a quite close resemblance to carolina. It seems possible, also, that durangoensis Viereck & Cockerell is the male.