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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Andrena milwaukeensis is a widespread, vernal, polylectic bee related to A. vicinoides, though not closely; There are two types of females of milwaukeensis, a western form in which metasomal terga 1-4 or 5 have abundant, long, fox-red hair and an eastern form in which only terga 1 and 2 have long ochraceous to red hair; A broad zone of intergradation occurs across northern United States and Canada and subspecies are not here recognized; The female of milwaukeensis in typical (eastern) form is similar to that of vicinoides in having basal mandibular teeth, dark tergal hairs, dark scopal hairs and pale thoracic dorsum; However, the milwaukeensis females have a longer clypeus with sparser punctures, an apically rounded pygidial plate, the pale vestiture usually fox-red, and the labral process less sharply bidentate; The male of milwaukeensis differs from that of vicinoides by having the sixth sternum flat (not reflexed along apical margin) and is marked by a relatively long first flagellar segment and short rounded basal mandibular teeth.
FEMALE. MEASUREMENTS AND RATIOS. — N = 20; length, 9-13 mm; width, 2.5-3.5 mm; wing length, M = 4.70 ± 0.226 mm; FL/FW, M = 1.03 ± 0.039; FOVL/FOVW, M = 3.24 ± 0.035.
INTEGUMENTAL COLOR. — As in vicinoides but tibial spurs usually testaceous.
STRUCTURE. — Antennal scape length equals first two and one-half flagellar segments or slightly more; flagellar segment 1 as long as following two and one-half segments, segment 2 about as long as broad and slightly shorter than 3; Eyes each about three and three-fourths times as long as broad, inner margins parallel; Mandible as in vicinoides; Malar space moderately long, minimum length one-third as long as width of mandibular base or slightly less; Galea as in frigida; Maxillary palpus as in frigida but segmental ratio about as 0.9:1.0:0.8:0.8:0.7:0.7; Labial palpus as in frigida but ratio about as 1.0:0.7:0.6:0.6; Labral process trapezoidal to squarish, slightly reflexed apically, emarginate with blunt teeth apically, basally with transverse depression; labrum apical to process with weak median crista, flat, shiny; Clypeus long, rounded from side to side, punctures of irregular size and spacing, separated by half to one or two puncture widths, smaller near base; surface shiny except basal fourth or more shagreened; Supraclypeal area as in vicinoides; Face above antennal fossae as in vicinoides but rugulae often coarser especially near facial foveae; Facial fovea as in vicinoides; Vertex above lateral ocellus usually equal to slightly less than one ocellar diameter, sculptured as in vicinoides but terga 2 and 3 with basal area punctures denser, separated mostly by half to one puncture width; Pygidial plate V-shaped with rounded apex, broad with internal raised triangular area; Sterna as in vicinoides.
VESTITURE. — Head entirely black except face and posteriorly on vertex often with red or ochraceous hair; Thorax black except dorsum with fox-red to ochraceous hair (usually red).
Metasomal terga black except terga 1 and 2 or 1 to 4 with long fox-red to ochraceous hair except at extreme lateral surfaces of terga 2 to 4; sternal hairs black; Leg hairs entirely black; Form and distribution of pollen-collecting hairs as in vicinoides.
MALE. MEASUREMENTS AND RATIOS. — N = 20; length, 8-12 mm; width, 1.5-2.5 mm; wing length, M = 3.63 ± 0.243 mm; FL/FW, M = 1.00 ± 0.006; FS1/FS2, M = 1.53 ± 0.031; INTEGUMENTAL COLOR. — As in vicinoides but tibial spurs testaceous and tergal apical areas usually dark.
STRUCTURE. — Scape length usually less than first two flagellar segments; flagellar segment 1 terete, one and one-third to two times as long as second segment and usually longer than segment 3, segment 2 usually longer than broad and shorter than segment 3, median segments one and one-half times as long as broad; Eyes about three times as long as broad, inner margins parallel; Mandibles long, decussate, as in vicinoides but basal inferior tooth small, rounded; Malar space, galea and maxillary palpus as in female; Labial palpus as in female but segmental ratio about as 1.0:0.6:0.6:0.5; Labral process as in female but usually smaller; labrum apical to process usually without crista, shiny; Clypeus moderately flattened, punctures separated mostly by half a puncture width, slightly sparser apicomedially, impunctate midline usually narrow, weak or absent; surface shiny; Supraclypeal area and face above antennal fossae as in female; Vertex as in female but above lateral ocellus usually as tall as one ocellar diameter and in large specimens taller; Genal area broad, as in vicinoides; Thoracic form and sculpturing as in vicinoides.
Metasomal terga 1-5 sculptured as in vicinoides; Pseudopygidial area absent or extremely narrow; Sterna 2-5 sculptured as in vicinoides; Sternum flat apically, not reflexed.
Terminalia as in figures 102-106.
VESTITURE. — Generally ochraceous to fox-red except as follows: face between upper ends of compound eyes and along inner margins eyes black; genal area entirely black to black in upper fourth or less; tergum 2 apically or tergum 3 apically and terga 4 and 5 entirely dark brown to black; sternal hairs brown or largely so; tarsi with inner surfaces pale yellow.
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.; face very slightly longer than broad; clypeus moderately convex, slightly broader than long, smooth, with widely spaced, shallow and rather fine punctures; facial foveae broad above, covered with brownish tomentum; space between margin of vertex and lateral ocelli subequal to their diameter; cheeks considerably broader than eyes, with minute, well separated punctures; malar space equal to about one-third the basal width of mandible; basal segment of flagellum longer than 2nd and 3rd combined; process of labrum extensive, much broader than long, the tip truncate with a very small median emargination; mandibles rather short, with a small subapical inner tooth; pubescence of head rather copious, fuscous in general but with some ochraceous pubescence on vertex and around antennae; thoracic integument dull and tessellate, very obscurely punctate; enclosure of propodeum smooth; thoracic pubescence long, dense and erect, pale ochraceous above, becoming slightly more fuscous beneath; propodeal corbicula rather well developed, pale ochraceous; trochanteral floccus well developed, fuscous; tibial scopa short, dense, of simple hairs, fuscous; fore and hind basitarsi slightly narrower than their tibiae, the mid basitarsi subequal to their tibiae; pubescence of legs blackish; 2nd submarginal cell much shorter than 3rd, receiving 1st recurrent toward tip; abdominal terga smooth but dull, punctures exceedingly minute and obscure, but rather close, apical margins hardly at all depressed, pubescence rather short but dense and erect, ochraceous on terga 1 and 2, fuscous on the remainder.
MALE — Length 9 mm.; face somewhat longer than broad; clypeus rather flat, only slightly broader than long, surface smooth and shining, with rather close, fine punctures; space between margin of vertex and lateral ocelli slightly exceeding their diameter; cheeks much broader than eyes, subangulate, angle opposite middle of eye (as in tridens, fig. 21) quite sparsely and minutely punctate; malar space short but distinct; process of labrum short and broad, the apical margin broadly and slightly emarginate; mandibles exceedingly long and slender, tip of one about reaching base of the other, without a subapical inner tooth, with a ventral, basal, triangular projection; pubescence of head rather long and dense, ochraceous except for some fuscous hairs around bases of antennae and on vertex laterally; thoracic integument dull, densely tessellate, punctures inevident; propodeal enclosure smooth; thoracic pubescence long, dense, and erect, reddish-ochraceous; basitarsi narrow and elongate, much narrower than their respective tibiae; 2nd submarginal cell much shorter than 3rd, receiving 1st recurrent near middle; abdominal terga shining, nearly impunctate, punctures being exceedingly minute and obscure, apical margins only very slightly depressed, slightly reddened, pubescence rather long and dense on terga 1 and 2 where it is entirely pale, much shorter and darker on the following terga; apical portion of sternum 8 narrow, sides nearly parallel, tip beyond the subapical ridge very short, very slightly incised medially; penis valves broadly expanded basally, excavated beneath this expansion, gonocoxites rather broadly expanded apically, gonocoxal lobes produced and broadly rounded.
DISTRIBUTION — Minnesota to the New England states, Quebec and Nova Scotia, south to North Carolina and Georgia; April to July.
FLOWER RECORDS — Aruncus, Ilex and Viburnum. Brittain and Newton (1934) record it also on Cornus, Pyrus malus and Rubus.