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 8-10 mm.; lateral ocelli subequally distant from margin of vertex and each other; cheeks slightly narrower than eyes, posterior margin not distinctly carinate; longer side of basal segment of flagellum somewhat shorter than segment 2 which is much elongated, median segments considerably longer than broad; mandibles slender and simple apically; wings subhyaline basally, becoming rather deeply infuscated along narrow outer margin and in marginal cell, with the usual three submarginal cells, 2nd much broader than 3rd anteriorly, veins piceous, basal vein much basad of transverse median; tegulae shining between very minute, quite sparse punctures; posterior margin of scutellum only slightly impressed medially; front coxae not spinose; apex of hind tibiae with 3 or 4 slender, elongate, yellowish, hair-like bristles; face largely ferruginous, lower half somewhat more testaceous, labrum bright yellow around basal and lateral margins, a restricted black area between and slightly above antennae, another between ocelli, and posterior half of cheeks black, the eyes completely encircled with reddish-testaceous; antennal scape reddish-testaceous, flagellum more brownish-testaceous below, dull ferruginous above; thorax in large part ferruginous, tegulae somewhat more yellowish-ferruginous; prothorax laterally, mesopleura below, metapleura and narrow adjacent margin of propodeum, and median lines on scutum and posterior face of propodeum, black; legs largely testaceous, front and mid femora darkened at base, hind femora largely dark, spurs pale yellow; abdominal terga largely ferruginous, basal tergum narrowly piceous base, terga 2 and 3 with large, lateral, yellow maculae that are widely separated medially, tergum 5 with a pair of subapical, slightly separated, yellow maculations, impressed apical margins of all quite broadly impunctate, somewhat more yellowish; abdominal sterna piceous in large part, becoming somewhat more testaceous on the more apical sterna; vertex and face above antennae very coarsely, closely and deeply punctate, cheeks becoming somewhat more rugose, lower part of face coarsely and deeply punctate at each side, but supraclypeal area and clypeus with very fine, close, shallow and rather obscure punctures; scutum and scutellum very coarsely, deeply and closely punctate, the mesopleura more rugose, punctures becoming somewhat more distinct below; propodeum posteriorly rather finely, obscurely and shallowly rugose, lateral faces becoming somewhat smoother below; discs of abdominal terga finely and rather closely and deeply punctate toward base, punctures becoming more minute and sparse toward the broad, apical, impunctate margins; basal tergum becoming impunctate laterally and basally, very minutely punctate medially; tergum 6 becoming rather sparsely, coarsely and deeply punctate toward apical rims; pseudopygidium transverse, very short forming the rather broadly truncate apical margin of tergum 5. densely clothed with suberect, silvery tomentum; pubescence very short and thin, entirely whitish, somewhat more copious on thorax laterally and posteriorly, very fine and obscure on abdomen, apex of sternum 5 with a dense patch of elongate, curved and convergent, fuscous hairs on each side.
MALE—Length 7-9 mm.; lateral ocelli very slightly nearer margin of vertex than to each other; cheeks considerably narrower than eyes, posterior margin not distinctly carinate; antennal scape only slightly swollen, apex deeply excavated and largely enclosing pedicel, basal segment of flagellum in front only half the length of segment 2, median segments somewhat longer than broad, 3-5 slightly swollen beneath; mandibles slender and simple apically; wings hyaline basally, becoming lightly infuscated apically and in marginal cell, with the usual three submarginal cells, 2nd usually somewhat broader than 3rd anteriorly, but these sometimes equal, veins largely piceous, basal vein much basad of transverse median; tegulae shining between very minute, sparse punctures; posterior margin of scutellum quite deeply impressed medially; front coxae not spinose; hind femora slender and unmodified; face below antennae largely yellow, median area of face above antennae and around ocelli, black, narrowly ferruginous around margin of eye above and posteriorly, becoming narrowly yellow on cheeks below, cheeks medially and posteriorly black; antennal scape bright yellow anteriorly, narrowly piceous posteriorly, flagellum brownish-testaceous; tubercles and tegulae more yellowish; pronotum black, the collar testaceous; mesopleura largely ferruginous above, black below, the scutum with a median, rather broad, black area, otherwise ferruginous ; scutellum entirely ferruginous, the metapleura and propodeum largely black; legs testaceous in large part, front and mid legs more or less yellowish anteriorly and their tarsi yellow, hind basitarsi more brownish, all spurs pale yellow; abdominal terga reddish-testaceous in part, tergum 1 blackish toward base, apical margin more ferruginous, 2 and 3 with broad, transverse, sub-basal bands that are slightly interrupted medially, apical areas more ferruginous, 4 with rather widely separated, lateral, yellow maculae, the median area more piceous, the broad depressed rim somewhat yellowish-hyaline, 5 and 6 rather broadly yellow medially, apical rims yellowish-hyaline; discs of abdominal sterna yellowish to testaceous, the broad, impunctate, apical rims more testaceous, sternum 6 bright yellow medially toward apex; vertex and face above antennae very coarsely, deeply and closely punctate, the cheeks becoming more finely rugose below, lower part of face rather deeply punctate on each side, and punctures of supraclypeal area rather coarse and very close; clypeus very finely and closely punctate beneath rather dense pubescence; scutum, scutellum and mesopleura very coarsely rugoso-punctate, posterior face of propodeum somewhat more finely rugose, lateral faces becoming somewhat smoother below, propodeal triangle smooth and somewhat shining below, becoming rather coarsely but irregularly rugoso-striate above; discs of abdominal terga very finely, closely and rather shallowly punctate, basally the punctures becoming somewhat more minute, but invading apical margins nearly to the rims, tergum impunctate laterally and basally, 4-6 becoming somewhat more coarsely and sparsely punctate toward the depressed apical rims; pubescence rather copious over head and thorax, rather short but entirely white, quite dense on face, on cheeks below, on thorax laterally and below, very fine and obscure on abdomen, becoming somewhat more elongate on the more apical terga, more elongate but very fine and sparse on sterna, becoming quite dense at apex of sternum 6; median length of pygidial plate about equal to basal width, rather strongly narrowed to the apex which is very deeply incised, margins carinate, surface closely and rather finely punctate; exposed sternal plates unmodified, sternum 6 strongly narrowed to the narrowly rounded tip; sternum 8 with a slender apical process; gonocoxites of genital armature as shown (fig. 107).
DISTRIBUTION — North Dakota to Nova Scotia, south to Tennessee and North Carolina, April to August.
FLOWER RECORDS — Azalea, Oenothera, Rubus and Senecio. This is recorded by Robertson (1929) on Antennaria, Claytonia, Dentaria, Erigeron, Nothoscordum, Oxalis, Salix, Smilacina, Taenidia, Viburnum and Zanthoxylum.
There is either a considerable range of variation in cressonii, or more than a single species is included in the material at hand. The differences involve the relative lengths of the antennal segments, the relation of the basal vein to the transverse median vein, and the extent of red coloration of the thorax. Both sexes show much the same variations, but there is no correspondance of these variations with distribution and sex.