Reprinted with permission from: Mitchell, T.B. 1962 Bees of the Eastern United States. North Carolina Agricultural Experiment Station Technical Bulletin No. 152.
FEMALE—Length 11-13 mm.; entirely black; face much longer than distance between eyes; eyes subparallel; lateral ocelli nearer each other than to eyes, and much nearer eyes than to margin of vertex; clypeus broadly convex, apical margin quite strongly outcurved, but median third or fourth narrowly produced and very slightly incurved, the margin of this area polished and impunctate; mandibles broad apically, 4-dentate; width of cheeks about twice that of eyes; wings subhyaline basally, becoming lightly infuscated apically, veins and stigma piceous; tegulae brownish-piceous, smooth and shining; legs entirely black, front spurs hyaline in part, mid and hind spurs black; pubescence rather thin but somewhat elongate, rather copious and pale around antennae, becoming somewhat blackish on vertex and clypeus, cheeks below, on pleura and over most of legs; pubescence largely pale on scutum, scutellum and posterior face of propodeum; abdominal tergum 1 largely pale pubescent, 2 pale pubescent in part, 3-6 largely black pubescent, 1 and 2 subfasciate apically toward sides; scopa entirely blackish; punctures fine and rather close over most of head and thorax, becoming somewhat more widely separated on vertex medially and on scutum posteriorly; abdominal terga shining, punctures minute and widely separated medially, interspaces being many times diameter of punctures, these becoming much closer toward the extreme lateral margins, tergum 5 more closely punctate, 6 with fine, crowded punctures, with a narrow, rounded, apical lip; sternum 6 triangularly pointed medially.
MALE—Length 9 mm.; entirely black; face nearly twice as long as distance between eyes; eyes subparallel; lateral ocelli slightly nearer eyes than to each other, slightly nearer each other than to margin of vertex; median segments of flagellum about as broad as long, apical segment more elongate, tapering apically (fig. 23); clypeus only slightly convex, broadly produced apically, nearly as long as the greatest breadth, apical margin nearly straight; mandibles bi-dentate; cheeks somewhat broader than eyes; wings hyaline at extreme base, becoming lightly infuscated apically, veins and stigma piceous; tegulae piceous, smooth and shining, with scattered, minute puncture evident; legs entirely black, anterior spurs more yellowish-hyaline, mid and hind spurs piceous or black; tergum 7 much broader than long, rather broadly rounded apically, with a submedian, depressed area; sterna 1-5 exposed, smooth and shining in large part, 1 and 2 each with a median, apical, spine-like projection, with only a few scattered punctures, 6-8 retracted, form as shown(fig. 24); genital armature as shown; pubescence of head and thorax largely pale, rather thin but somewhat elongate, subappressed between antennae and eyes, clypeus with dense, appressed tomentum; legs with short, black pubescence except for the pale posterior fringe on front tarsi; abdomen not fasciate, discal pubescence of the terga extremely short, thin and inconspicuous, tergum 6 sometimes obscurely fasciate apically.
DISTRIBUTION—British Columbia to Maine and Nova Scotia, north to Hudson Bay and Alaska, May to August.
FLOWER RECORD — Phacelia.
There are two additional forms of albifrons occurring in the West, argentifrons (Cresson) and maura (Cresson)