Reprinted with permission of the American Entomological Society from:
LaBerge, W. E., Ribble, D. W. 1975. A revision of the bees of the genus Andrena of the Western Hemisphere. Part VII. Subgenus Euandrena. Transactions of the American Entomological Society 101: 371-446.
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This small species is very similar to A. nigrihirta from which it can be distinguished only with difficulty especially in the male sex. The main characteristics by which algida differs from nigrihirta are the broader facial quadrangle of both sexes and the clypeus, especially in females, which is shorter, more evenly rounded from side to side, and with smaller and more regularly sized punctures. The clypeus is often moderately dulled throughout by fine shagreening. In addition, the tergal apical pale bands, when present, are composed of longer, sparser, weaker hairs than in nigrihirta. The dark males of algida and nigrihirta present the most difficulties in distinguishing between the two species, but the broader face plus the slightly shorter first flagellar segment of algida will usually suffice.
FEMALE. MEASUREMENTS AND RATIOS. — N = 20; length, 8-10 mm; width, 2.5-3.5 mm; wing length, M = 3.46 ± 0.080; FL/FW, M = 1.02 ± 0.005; FOVL/FOVW, M = 3.64 ± 0.075.
INTEGUMENTAL COLOR. — Black except as follows: mandible with apical half rufescent; flagellum dark brown to reddish-brown; tegula translucent, piceous to dark red; wing membranes slightly infumate, yellow, veins dark red to orange; terga with apices translucent, colorless at apex to rufescent basally; terga hyaline apically, often rufescent; distitarsi rufescent, hind basitarsi and tibia dark reddish-brown to red.
STRUCTURE. — Antennae, eyes, mandibles and galeae as in nigrihirta. Maxillary palpus as in nigrihirta but segmental ratio about as 1.0:1.0:0.9:0.7:0.6:0.7. Labial palpus as in nigrihirta but ratio about as 1.0:0.5:0.5:0.5. Labrum as in nigrihirta. Clypeus evenly rounded from side to side, with small round punctures relatively uniform in size and spacing, separated by half to one and one-half puncture widths, surface often moderately dulled throughout by fine shagreening but frequently shagreened only basally; relatively short. Supraclypeal area as in nigrihirta. Facial fovea short, narrow, much as in nigrihirta, separated from lateral ocellus by one and one-half to two ocellar diameters. Vertex short as in nigrihirta. Genal areas as in nigrihirta.
Thoracic form and sculpturing as in nigrihirta. Wing venation and vannal lobe of hind wing as in lawrencei. Tibial spurs and tarsal claws normal as in nigrihirta.
Metasomal sculpturing and pygidial plate as in nigrihirta.
VESTITURE. — Usually white except dorsal thoracic hairs ochraceous to yellow and facial fovea with short brown hairs. Darker specimens may have facial hairs largely brown, mesepisterna largely brown to mixed dark in upper thirds, mesoscutum and scutellum with a few brown hairs medially, and short tergal hairs brown. Leg hairs including scopae rarely dark in color except hairs on and surrounding basitibial plate and on apical half of fore femur and outer surface of fore tibia. Pollen-collecting hairs as in nigrihirta (except color).
MALE. MEASUREMENTS AND RATIOS. — N = 20; length, 7-10 mm; width, 1.5-2.5 mm; wing length, M = 3.06 ± 0.153 mm; FL/FW, M = 1.02 ± 0.006; FS1/FS2, M = 1.25 ± 0.031.
INTEGUMENTAL COLOR. — Black with same exceptions as in female; wing veins usually reddish-brown, rarely pale, membranes hyaline.
STRUCTURE. — Antenna as in nigrihirta and lawrencei but flagellar segment 1 about as long as segment 3 or slightly shorter and distinctly longer than segment 2 which is quadrate or slightly longer than broad. Eyes, mandibles and galeae as in nigrihirta. Maxillary palpus as in nigrihirta but segmental ratio about as 1.0:1.0:1.0:0.8:0.6:0.8. Labial palpus as in nigrihirta but ratio about as 1.0:0.4:0.3:0.4. Labrum as in nigrihirta. Clypeus as in female but more often shiny, supraclypeal area, vertex, genal area, and face above antennal fossae as in nigrihirta.
Thoracic form and sculpturing, wing venation and vannal lobe hind wing as in nigrihirta. Tibial spurs and tarsal claws normal.
Tergal and sternal sculpturing as in nigrihirta. Terminalia as in figures 25-29; note the following: genital capsule as in nigrihirta but penis valves much narrowed medially, gonocoxite rounded apically; sternum 8 much broadened at apex.
VESTITURE. — Generally white as in female; more often pale than dark; darkest forms with head except vertex, pleurae and short tergal hairs dark brown.
VARIATION. — Considerable variation exists in the shagreening of the clypeus and the spacing of clypeal punctures. This variation shows no geographical dines.
The dark specimens of both sexes are most abundant in Colorado but an occasional dark specimen appears in series from throughout the Rocky Mountain Region and north to the North-west Territories in Canada. It seems probable that some intergression occurs between nigrihirta and algida in the Rocky Mountains. Although algida does not seem to occur in the coastal states and provinces, a few specimens from the Sierra Nevada Mountains adjacent to Nevada (placed by us with nigrihirta ) show some characteristics of algida (such as finer clypeal punctures). These intermediate forms are all dark specimens.
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 10 mm.; clypeus rather strongly convex, projecting not quite one-half below suborbital line, rather dull, punctures quite distinct but rather shallow, rather sparse medially, becoming quite close but more obscure laterally; facial foveae narrow and quite short, occupying above no more than half of area between eyes and ocelli, covered with brownish tomentum; space between margin of vertex and lateral ocelli subequal to their diameter; cheeks subequal to eyes in width, rounded posteriorly, dull, very obscurely punctate; malar space short; basal segment of flagellum subequal to 2nd and 3rd combined; process of labrum rather large, about twice as broad as long, imperfectly semicircular; pubescence of head, thorax and legs entirely white; thoracic integument dull, quite densely tessellate, punctures of scutum very shallow and obscure, well separated anteriorly but not sparse, becoming rather sparse but more minute and obscure posteriorly, those on scutellum scattered, irregular and obscure; pleura densely tessellate, punctures inevident; enclosure of propodeum dull, tessellate, obscurely subrugose toward base; propodeal corbicula very poorly developed, without an anterior fringe; trochanteral floccus rather short; tibial scopa quite dense, hairs moderately long, simple, entirely white; hind tibiae slender and elongate, all the basitarsi slightly narrower than their respective tibiae; 2nd submarginal cell nearly as long as 3rd, receiving 1st recurrent near middle; abdominal terga somewhat shining, very minutely and rather sparsely punctate, apical depressed areas rather narrow and obscure, becoming hyaline along rims, pubescence short, thin, suberect, entirely white, forming loose apical fasciae on terga 2-4, that on tergum 2 interrupted medially, tergum 5 with a quite dense, pale brownish, apical fimbria.
MALE. — Length 7 mm.; clypeus rather strongly protuberant and convex, projecting about one-half below suborbital line, rather uniformly, deeply, finely and rather closely punctate beneath the quite dense, fuscous pubescence; space between margin of vertex and lateral ocelli subequal to their diameter; cheeks very slightly broader than eyes, somewhat flattened, rounded posteriorly, surface dull, punctures very obscure; length of malar space nearly one-third basal width of mandible; basal segment of flagellum very slightly longer than 2nd segment, subequal to 3rd; process of labrum fully twice as broad as long, slightly narrowed apically, apex quite broadly truncate; mandibles rather short, nearly straight, with a distinct, inner, subapical tooth, scarcely overlapping; pubescence of head fuscous on clypeus, inner margins of eyes, between antennae and on cheeks above, whitish on cheeks below, between clypeus and antennae and on vertex; thoracic integument dull, densely tessellate, scutum, scutellum, and pleura practically impunctate; enclosure of propodeum dull and densely tessellate; pubescence of thorax and legs largely whitish, a few dark hairs on each extreme side of scutum; basitarsi slender and elongate, narrower than their tibiae; 2nd submarginal cell considerably shorter than 3rd, receiving 1st recurrent slightly beyond middle; abdominal terga smooth and somewhat shining, punctures exceedingly minute and rather sparse, apical depressed areas rather narrow but distinct, reddish-hyaline, discal pubescence short, suberect, entirely pale, fasciae not developed; apical portion of sternum 8 rather short, narrow basally, but rounded and slightly dilated apically, not protuberant ventrally, and very sparsely and thinly pubescent; penis valves slender, slightly expanded basally, gonocoxites also quite slender, very slightly dilated apically, gonocoxal lobes produced, narrowly rounded.
DISTRIBUTION. — Minnesota to Nova Scotia and Hudson's Bay, including Michigan. New York and the New England states; April to June.
FLOWER RECORDS. — Brittain & Newton (1934) record this species on Fragaria.
Lanham (1949) assigned algida to Gonandrena, but the type has been examined by this writer and in his opinion it is synonymous with fuscisignata Viereck which Lanham assigned to Thysandrena. Moreover, algida bears little resemblance to the other species of Gonandrena.
Described under the synonymous name: Andrena albisigna
FEMALE. — Length 8 mm.; face somewhat longer than broad; clypeus strongly convex, somewhat produced, projecting nearly two-thirds below suborbital line, smooth and shining, deeply and rather coarsely punctate, punctures sparse in center, becoming rather close laterally; facial foveae narrow, occupying above no more than half of area between eyes and ocelli, covered with silvery tomentum; space between margin of vertex and lateral ocelli subequal to their diameter; cheeks broader than eyes, rounded posteriorly, smooth but rather dull, punctures inevident; malar space short but evident; basal segment of flagellum slightly longer than 2nd and 3rd combined; process of labrum quite large, broadly rounded, length about half the basal width; pubescence of head, thorax and legs entirely pale ochraceous; thoracic integument dull and tessellate, punctures of scutum shallow, but quite distinct, well separated but not sparse on scutum and scutellum; punctures of pleura minute and obscure; enclosure of propodeum finely roughened basally; propodeal corbicula poorly developed, short, pale ochraceous, anterior fringe indefinite; trochanteral floccus very short and poorly developed, pale ochraceous; hind tibiae slightly broadened apically, the scopa well developed, of simple, moderately elongate hairs, entirely pale ochraceous: fore and hind basitarsi considerably narrower than their tibiae, but mid basitarsi nearly as broad as mid tibiae; 2nd submarginal cell much shorter than 3rd, receiving 1st recurrent near middle; abdominal terga smooth but rather dull, punctures exceedingly minute, obscure and sparse, apical depressed areas rather shallow medially, occupying about one-third median length of disc, brownish-hyaline, becoming more yellowish toward rims, discal pubescence very short, thin, erect, entirely pale, fasciae very poorly developed, tergum 5 with a pale brownish, apical fimbria.
DISTRIBUTION. — The New England states, south to Tennessee; June and July.
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