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 17-18 mm., breadth of abdomen 8-8.5 mm.; black, apical tarsal segments becoming brownish-testaceous, spurs testaceous; wings lightly infuscated, veins testaceous to piceous; pubescence of scutum and scutellum pale yellowish, with a limited area of fuscous on scutum posteriorly, yellow on tubercles and adjacent area of pleura, otherwise fuscous or black on head, thorax and legs; abdominal terga 1-3 with erect fuscous pubescence, that on 4 conspicuously yellow, more elongate laterally, and tergum 5 with elongate, fuscous pubescence, sterna with relatively thin, dark pubescence throughout; clypeus closely and finely punctate; lab- rum triangularly produced at base on each side, median area depressed, densely fringed apically with fuscous hairs; apex of mandible faintly crenulate but not distinctly dentate, outer face somewhat shining, with a few, minute, irregular punctures; malar space shining with distinct punctures, somewhat shorter than basal width of mandible, eye nearly 5 times as long; lateral ocelli subequally distant from eyes and each other, this about half the distance to margin of vertex; scape somewhat more than half the length of the flagellum, basal segment of flagellum slightly longer than segment 3, and 3 slightly longer than 2; facial punctures below ocelli and on vertex medially very fine and close, becoming more shining and somewhat more sparsely punctate laterally, a shining area adjacent to each lateral ocellus impunctate; median posterior area of scutum shining, with rather coarse, deep, distinct and somewhat separated punctures, otherwise punctures of thorax very fine and close; sternum 6 not protuberant, subtriangular, smooth and shining medially, slightly elevated laterally just before apex.
MALE—Length 12-16 mm., breadth of abdomen 5-7 mm.; black, apical tarsal segments brownish-testaceous, spurs testaceous; wings very faintly infuscated, veins yellowish to piceous; pubescence of head long and erect, largely black, with only a very few intermixed pale hairs on vertex; anterior half of scutum and area around tubercles with long, copious, erect, yellowish pubescence, this extending narrowly along margins of scutum, posterior half largely covered with blackish pubescence; scutellum with intermixed, short, black hairs and long yellow hairs; thorax otherwise black pubescent laterally, posteriorly and beneath; legs largely black pubescent basally, the basitarsi more or less conspicuously fringed with elongate, fuscous hairs, apical tarsal segments with relatively short, pale pubescence; abdominal terga 1 and 4 pale yellowish pubescent, hairs long and copious; terga 2 and 3 and 5-7 black pubescent, at least medially, 5 and 6 with elongate yellowish hairs evident laterally; clypeus and labrum quite closely and finely punctate, apical margin quite strongly depressed, evenly rounded; mandibles very short, with a small subapical tooth near the tip above, and with a prominant fringe of elongate fuscous hairs below, outer surface rather dull and impunctate; malar space smooth and shining, very slightly shorter than basal width of mandible, eye about five times as long; lateral ocelli very slightly nearer eyes than to each other, much more widely removed from margin of vertex; segment 3 of flagellum very slightly longer than basal segment, segment 2 much shorter; sterna 7 and 8 and genital armature similar to variabilis (fig.
DISTRIBUTION—Saskatchewan to New Brunswick, south to Michigan, Ohio and the New England States, May to October.
HOSTS—Plath (1934) lists Bombus affinis and B. terricola as hosts of ashtoni.