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 7-8 mm.; lateral ocelli slightly nearer margin of vertex than to each other; cheeks considerably narrower than eyes, posterior margin strongly carinate; longer side of basal segment of flagellum equal to segment 2, median segments slightly longer than broad; mandibles simple; wings subhyaline basally, becoming rather deeply infuscated along outer margin and in marginal cell, with a hyaline area just beyond the submarginals, with the usual three submarginal cells, 2nd somewhat broader anteriorly than 3rd, veins piceous, basal vein much basad of transverse median; tegulae shining between deep, distinct, quite close punctures; posterior margin of scutellum deeply impressed medially; front coxae with triangular, posterior, spine-like tubercles; apex of hind tibiae with two or three long, yellowish, hair-like bristles; head and thorax largely ferruginous, but face somewhat more testaceous, with a small amount of black between antennae, between ocelli, and along posterior margin of cheeks; tubercles, tegulae and legs more testaceous; scutum with median black line, and metapleura and adjacent anterior margin of propodeum, black; spurs pale yellow; discs of abdominal terga ferruginous, basal tergum narrowly blackish piceous at base and along apical margin, terga 2-4 more or less piceous apically, 2 and 3 with lateral, widely separated, yellow maculae; antennal scape and base of flagellum more testaceous, following segments ferruginous beneath, more piceous above; punctures of face above antennae very coarse, deep and close, becoming somewhat finer on vertex, shallow but quite coarse and close on each side of face below, cheeks more coarsely rugose, supraclypeal area more finely rugoso-punctate, the clypeus finely and shallowly punctate; scutum coarsely rugoso-punctate medially, becoming somewhat more finely so laterally, the scutellum and pleura quite coarsely rugoso-punctate above, punctures becoming somewhat more distinct and finer on pleura below; propodeum rather finely rugose posteriorly, becoming very finely so on each lateral surface, triangle smooth and somewhat shining below, becoming quite coarsely striate on each side above, more finely reticulate medially; discs of abdominal terga very finely and rather closely punctate, apical impressed areas largely impunctate, invaded only slightly by very minute, sparse punctures, tergum 1 becoming impunctate basally and laterally; punctures of tergum 5 somewhat more coarse and distinct, well separated apically; pseudopygidium very short, transverse, forming the rather narrowly truncate apical margin of tergum 5, densely clothed with suberect silvery tomentum; pubescence very short, inconspicuous, somewhat more elongate on cheeks below and on pleura and propodeum, entirely pale where visible, hardly evident on abdomen dorsally, somewhat more elongate but very fine and sparse on abdominal sterna; sternum 5 with a dense, transverse tuft of elongate, brownish, convergent hairs on each side of mid-line apically.
MALE—Length 7-9 mm.; lateral ocelli subequally distant from margin of vertex and each other; cheeks much narrower than eyes, posterior margin quite strongly carinate; antennal scape only slightly swollen, apex deeply excavated, completely enclosing pedicel, longer side of basal segment of flagellum equal to segment 2, median segments only very slightly longer than broad, each of segments 2-7 with a basal depression above, resulting in a tuberculate appearance of the apex; mandibles rather robust, entirely simple; wings subhyaline basally, becoming rather deeply infuscated apically and in marginal cell, a hyaline area just beyond the submarginals, with the usual three submarginal cells, 2nd somewhat broader anteriorly than 3rd, veins testaceous to piceous, basal vein much basad of transverse median; tegulae shining, punctures fine but close, deep and distinct throughout; posterior margin of scutellum quite deeply depressed medially; front coxae with posterior, triangular, spine-like tuber. des; hind femora quite slender and unmodified; clypeus, labrum, mandibles, narrow lateral facial maculae ending rather abruptly at level of antennae, and supraclypeal area medially, bright yellow, and cheeks with a narrow, yellow band along margin of eye below; face above, vertex and cheeks otherwise black, the black area reaching lateral margins of clypeus below; antennal scape bright yellow anteriorly, becoming more ferruginous posteriorly, flagellum more brownish-testaceous beneath, piceous above; pronotal collar and a rather large maculation on pleura, bright yellow, pleural maculation bordered above and below with ferruginous; scutum and scutellum ferruginous, with a rather broad, median, black band on scutum; propodeum and metapleura largely black, the mesopleura becoming black beneath; tubercles and tegulae more testaceous; tergum 1 of abdomen, piceous basally and very narrowly piceous across apical margin, more ferruginous medially, with a small yellow maculation on each side; disc of tergum 2 ferruginous medially, with a large yellow maculation on each extreme side, apical margin becoming somewhat dark. er; terga 3-6 with more or less complete, transverse, yellow bands, these sub-basal or median on 2 and 8, more nearly apical on 5, narrowly interrupted medially on 3, becoming very broad at each extreme side, and broad on 4 laterally, posterior margins of the bands more or less emarginated on each extreme side; discs of abdominal sterna 2-4 more or less yellow medially, tergum 1 largely ferruginous, the more apical terga becoming more piceous apically, but tergum 6 largely testaceous; legs largely testaceous, hind femora more ferruginous, with piceous infusions, spurs pale yellow; punctures coarse, deep and close on face above antennae, somewhat shallower but quite coarse and very close below, very fine, close and shallow on clypeus; vertex posteriorly very closely and coarsely punctate, punctures becoming somewhat more sparse toward eyes, cheeks much more finely rugose; scutum, scutellum and mesopleura coarsely rugoso-punctate, punctures becoming somewhat more distinct on mesopleura below; propodeum posteriorly somewhat more finely rugose, becoming smoother on each side toward metapleural margin, triangle rather smooth below, becoming rather finely reticulate above medially, coarsely but narrowly striate on each side; discs of abdominal terga very finely and rather closely punctate, punctures sparsely invading the broad, impressed, apical margins nearly to the rims, tergum 1 becoming impunctate laterally and basally, terga 5 and 6 becoming more coarsely and sparsely punctate apically; pubescence entirely pale, very short, somewhat more copious on face and on thorax laterally, posteriorly and beneath, barely evident on abdomen dorsally, sternal plates with more sparse but elongate, fine, pale hairs, sternum 6 becoming quite densely short pubescent apically; median length of pygidial plate hardly equal to basal width, slightly narrowed apically, apex broadly truncate and slightly emarginate, margins carinate, surface with rather close but distinct, fine punctures; exposed abdominal sterna unmodified, sternum 6 subtriangular, apex narrowly rounded; sternum 8 with a slender apical process; gonocoxites of genital armature as shown (fig. 107).
DISTRIBUTION—Minnesota to New York, south to Georgia, March to May.
FLOWER RECORDS—Crataegus, Prunus, Rubus, Salix and Stellaria. Robertson
(1929) records this species on Amelanchier, Cardamine, Cercis, Erigeron, Geranium,
Ribes, Taenidia, Taraxacum, Thaspium, Zanthoxylum and Zizia.
It seems doubtful that there is any real difference between denticulata and simplex Robertson. In Robertson’s key (1903) the males are separated by the color of the abdomen, but there is considerable variation in this character and is thus unreliable. The short, triangular coxal spines of denticulata are included as a key character, but these vary in the relative degree of development, and are very poorly developed in a specimen that has been compared with the lectotype specimen and thought to be identical with it. The females Robertson associated with these males may or may not be correctly associated. There is need for a re-study of the Robertson material, but of more significance yet is the collection of a good series of both sexes from the nesting site of its unknown Andrena host.
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