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 11-12 mm., breadth of abdomen 4.5-5 mm.; black, the mandibles more or less yellow apically; segments of flagellum beyond the 2nd reddish-piceous below, black above; apical tarsal segments more brownish, the spurs pale yellow; tegulae brownish-testaceous; wings whitish-hyaline, veins testaceous to piceous; cheeks about as broad as eyes; clypeus but very slightly protuberant, its median length about half the distance between eyes below; eyes slightly converging below; segment 2 of flagellum slightly more than half the length of segment 1; clypeus very closely and distinctly punctate, punctures rather fine, those on labrum fully as coarse and nearly as close; supraclypeal area impunctate medially, lateral areas of face below level of antennae very finely and closely punctate, becoming minute but still rather close on shining surface above between eyes and ocelli, median area below ocelli more deeply and distinctly but quite closely punctate; vertex very finely and densely punctate behind ocelli, lateral punctures more distinct; cheeks somewhat shining, rather closely punctate, the punctures minute and indistinct along eye margin, becoming rather coarse and deep posteriorly; punctures of scutum quite coarse and deep, rather uniformly close, only slightly separated in center of disc posteriorly, those on scutellum about equally coarse and close; punctures of pleura somewhat finer and more shallow than those on scutum, slightly separated, becoming somewhat finer and more obscure posteriorly above mid coxae; posterior face of propodeum dull and tessellate, punctures rather shallow and well separated, dorsal area becoming rather coarsely reticulate on each side along the upper margin, lateral faces dull, punctures rather close and fine; basal abdominal tergum rather closely punctate across basal half of disc, the punctures sometimes shallow and obscure, becoming closer at extreme sides where they nearly reach apical margin, the broad, median, apical area impunctate; terga 2-4 finely punctate across basal areas, punctures well separated but not sparse on 2, becoming finer on 3, and almost crowded on 4, apical areas with scattered, exceedingly minute and rather sparse punctures; median length of pygidium about equal to basal width, subtriangular, with narrowly rounded apex; entire head and thorax with copious, quite dense, bright ochraceous or fulvous pubescence, with only a few inconspicuous dark hairs at all evident on scutellum and on scutum posteriorly; legs pale pubescent basally, but fore and mid tibiae with more or less fuscous pubescence on outer surface, basitarsi with dark brownish pubescence, hind tibial scopa yellowish, the hairs quite densely plumose; basal abdominal tergum with a small amount of short, subappressed, fuscous pubescence on each side of disc, otherwise with rather copious ochraceous pubescence basally and along lateral margins; discs of terga 2-5 with rather sparse, short, suberect, dark pubescence, this more sparse on the apical impressed areas; tergum 2 with a rather broad, basal, yellowish fascia, and 2 and 3 with submedian fasciae that fringe the apical impressed areas, that on 3 somewhat broader; apical area of tergum 4 largely covered with yellowish or whitish tomentum, this rather narrowly interrupted medially along the apical margin; terga 5 and 6 dark pubescent except for some lateral pale hairs.
MALE—Length 9-11 mm., breadth of abdomen 3.5 mm.; black, the clypeus entirely bright yellow, labrum with a basal, median, yellow maculation, and mandibles with subapical, more testaceous maculations; antennal flagellum brownish-testaceous beneath, piceous above; apical tarsal segments brownish-testaceous, spurs pale yellowish; tegulae rather dark anteriorly, becoming somewhat more yellowish-hyaline posteriorly; wings whitish-hyaline, veins yellowish to testaceous; margins of abdominal terga more or less yellowish; cheeks somewhat narrower than eyes; clypeus slightly protuberant, its median length somewhat greater than distance between eyes below; eyes quite strongly convergent below; basal segment of flagellum about equal to pedicel in length, segment 2 four or five times longer than segment 1 and pedicel combined; punctures of clypeus quite close laterally, becoming somewhat separated medially, rather obscure on the yellow surface, those on labrum somewhat deeper and more distinct; supraclypeal area impunctate medially, lateral areas of face below level of antennae very finely and closely punctate becoming minute and obscure but still rather close above where the surface is shining between eyes and ocelli, the more median punctures below ocelli much deeper and more distinct; vertex very finely and densely punctate behind ocelli, punctures becoming more distinct laterally; cheeks somewhat shining, punctures quite deep and distinct, well separated posteriorly, becoming minute toward eye margin; scutum and scutellum somewhat shining, the punctures rather sparse ir a restricted median area of scutum posteriorly, becoming very close laterally and anteriorly, those on scutellum about equal in size but rather sparse; pleura with rather coarse and deep punctures, these slightly but not widely separated, becoming much finer and closer posteriorly above mid coxae; propodeum rather dull and tessellate posteriorly, punctures shallow but rather close, dorsal area becoming rather coarsely reticulate along upper margin, lateral faces rather dull, quite closely punctate; basal abdominal tergum with quite deep and distinct punctures across base, these well separated, becoming more minute and sparse toward apical margin, much closer at each extreme side; terga 2-4 with fine but quite distinct punctures across basal area, these well separated on 2, somewhat closer on 3, quite close on 4, the apical impressed areas largely impunctate; tergum 5 quite densely punctate across base, with an obscure angle on each extreme side, and tergum 6 with an elongate, triangular, apical spine on each side; pubescence of entire head, thorax and legs pale ochraceous, the basal abdominal tergum largely pale ochraceous anteriorly and on lateral margins, the disc with suberect, more fuscous pubescence that is more evident laterally; discs of following terga with suberect, rather thin, dark pubescence which does not at all obscure the surface, more sparse on the apical impressed areas; tergum 2 with a narrow, basal, whitish fascia that is usually hidden by the preceding plate, and apical impressed area fringed by a narrow whitish fascia; impressed areas of 3 and 4 also fringed with whitish fasciae well removed from apical margin, that on 5 distinct but more nearly apical in position, 6 entirely dark pubescent; median length of pygidial plate about equal to basal width, margins carinate, rather strongly convergent apically to the abruptly constricted and truncate apex; sterna 7 and 8 and genital armature as in agilis (fig. 84).
DISTRIBUTION — Kansas and North Dakota, east to Maine and Georgia, July to October.
FLOWER RECORDS—LaBerge (1961) indicates that Helianthus is the primary source of pollen for trinodis, but he lists also species of Arctium, Asclepias, Aster, Bidens, Blephilia, Carduus, Cassia, Cirsium, Coreopsis, Dichophyllum, Grindelia, Helenium, Heliopsis, Lepachys, Liatris, Monarda, Pepo, Petalostemum, Ratibida, Rudbeckia, Silphium, Solidago, Symphoricarpos, Teucrium, Verbena, Vernonia and Veronica.