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 7 mm.; facial punctures deep and distinct, rather fine and well separated, interspaces somewhat exceeding diameter of punctures even on clypeus; process of labrum well developed and conspicuous, broadly rounded; punctures very fine and close on vertex medially, becoming very sparse and minute laterally, those on cheeks minute and well separated, becoming hardly visible toward outer orbits; pubescence of head rather thin, whitish above, somewhat yellowish on clypeus; thorax with whitish pubescence except for a patch of fuscous on scutum and scutellum; punctures of scutum fine but rather deep and distinct, well separated over most of disc, becoming quite close along the narrow posterior margin, those on scutellum rather irregular and variable, somewhat sparse anteriorly becoming densely crowded posteriorly; pleura smooth and somewhat shining, punctures fine but rather distinct, well separated; lateral and posterior faces of propodeum shining, with scattered, exceedingly minute and obscure punctures, dorsal area polished except for a very narrow, basal fringe of short, fine striae; wings subhyaline, veins and stigma brownish; tegulae brownish; legs dark, basal portions with whitish pubescence, tarsi with fuscous pubescence, scopa on hind tibae entirely white, that on basitarsi fuscous, with a small amount of basal, white pubescence; abdominal terga smooth and somewhat shining, punctures hardly evident, apical margins of terga more or less shallowly depressed, pale, apical fasciae poorly developed toward sides of terga 3-4, segment 5 with an apical fimbria which is fuscous medially, becoming whitish at extreme sides, 6 with a distinct pygidial area fringed on each side with dense fuscous pubescence.
MALE—Length 7.5 mm.; clypeus entirely yellow, with very small and inconspicuous facial maculae on each side between clypeus and eye, and the supraclypeal area very narrowly yellow along upper margin of clypeus, labrum and mandibles entirely black; facial punctures quite deep, distinct and rather close above antennae, becoming sparse and minute below; vertex finely and closely punctate medially, becoming sparse and irregular laterally, cheeks shining, with very minute, well separated punctures; pubescence of entire head pale ochraceous, becoming almost whitish below, that on thorax pale ochraceous above except for an obscure patch of fuscous hairs on scutum, becoming somewhat whitish below and posteriorly; punctures of scutum very fine, well separated, quite uniform over most of disc, those on scutellum slightly coarser and closer, especially toward posterior margin; pleura somewhat shining, punctures fine and well separated, becoming quite minute and sparse posteriorly; lateral and posterior faces of propodeum shining, with exceedingly minute, scattered punctures that are barely visible, dorsal area polished and impunctate, with a very narrow, basal fringe of short striae; wings subhyaline, veins and stigma brownish; tegulae brownish; legs dark, clothed with whitish pubescence, mid basitarsi quite slender, about equal in length to the following segments combined, hind basitarsi robust and broad, more or less truncate apically, not at all narrowed; abdominal terga smooth and shining, largely impunctate, shallowly depressed apically, with incomplete, thin, whitish, apical fasciae toward each side of segments 2-4; apex of gonocoxites demarked by a slight ridge bearing a few short hairs, gonostyli expanded to form two elongate, divergent lobes, inner lobe about twice as broad as outer lobe.
DISTRIBUTION — Colorado, Montana and southern Canada, east to New York, the New England states and Nova Scotia; June to September.
FLOWER RECORDS — Apocynum, Geranium, Rubus and Vaccinium.
Provancher described Eucera nuda in 1882. Later, believing it to be the same as Macropis ciliata Patten, he made it a synonym of that species. However, examination of the type in the Provincial Museum of Quebec shows that it is the same as Macropis morsei Robertson, which therefore becomes a synonym of nuda.