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 8-9 mm.; black; pubescence whitish, rather short and thin; head very slightly broader than long; clypeus somewhat convex, projecting about one-half below suborbital line; eyes only very slightly convergent below; cheeks subequal to eyes in width; lateral ocelli very slightly nearer margin of vertex than to eyes; punctures above antennae deep and distinct, slightly separated, becoming more sparse below, especially on supraclypeal area and clypeus, the latter nearly impunctate along apical margin, punctures of vertex and upper part of cheeks minute and obscure, very close, the cheeks becoming rather distinctly striate below; scutum somewhat shining, punctures quite close but variable as to size, being fine in general; scutellum with some very fine punctures along the median line and toward each side, otherwise quite smooth; pleura quite coarsely rugose; dorsal area of propodeum very finely rugoso-striate, posterior face densely pubescent, lateral carinae incomplete, extending only about half way to dorsal margin; wings lightly infuscated, becoming slightly more hyaline apically, veins and stigma ferruginous; tegulae piceous, with a yellowish hyaline anterior margin, legs almost entirely dark; the hind basitibial plate triangularly acute; basal tergum of abdomen somewhat shining, very minutely and quite closely and uniformly punctate, the following segments becoming progressively more minutely and obscurely punctate, segments 2 to 4 with dense, white, basal fasciae, that on 4 often hidden, discal pubescence very short and inconspicuous, entirely pale.
MALE—Length 6-7 mm.; black; apical half of clypeus yellowish or ferruginous; pubescence whitish, rather dense on lower portion of face and on thorax laterally; head somewhat broader than long; clypeus rather fiat, projecting about one half below suborbital line; eyes only very slightly convergent below; mandibles slender and simple, not greatly elongated; labrum broadly triangular, with a subacute, median, apical projection; cheeks subequal to eyes in width, becoming somewhat broader below to a broadly rounded posterior angle; lateral ocelli somewhat nearer margin of vertex than to eyes; basal segment of flagellum somewhat longer than pedicel, considerably shorter than the second and following segments which are ferruginous below, piceous above; punctures of face above antennae very fine, close and deep, becoming more sparse below, the supraclypeal area bare, with rather sparse, minute punctures, clypeus smooth and shining, impunctate except along basal margin; punctures of vertex minute and obscure, cheeks rather strongly striate, especially below; scutum shining, the punctures variable and scattered but rather deep and distinct, close laterally, those on scutellum sparse on each side of a median, more closely punctate impression; pleura very finely rugose; dorsal area of propodeum very finely striate, the median striae not quite attaining posterior margin, posterior face thinly pubescent, lateral marginal carinae incomplete; wings subhyaline, veins and stigma brownish-ferruginous; tegulae reddish-piceous, anterior margin yellowish; legs mostly dark, but the tarsi yellowish-ferruginous; basal abdominal terga shining, punctures minute but rather distinct, well separated on basal segment, becoming closer and more minute and obscure apically, terga 2-4 with dense, whitish, basal fasciae, the discal pubescence very sparse and obscure, slightly more yellowish; apical margin of sternum 5 nearly straight, 6 rather narrowly truncate apically; gonostylus robust, broadly rounded and densely fringed with setae, the ventral retrorse lobe rather narrow, well clothed with short pubescence.
DISTRIBUTION—British Columbia to Nova Scotia, southward through the New
England States, Wisconsin, Michigan and Ohio, to North Carolina; May to September.
FLOWER RECORDS—This species is recorded by Brittain and Newton (1934) on Cornus, Epilobium, Pyrus malus, Taraxacum and Veronica.
In the Sandhouse key (1933) the male of athabascense is separated from that of forbesii by the somewhat shorter mandibles, in addition to the color differences of the tarsi and antennae. We have been unable to find any real difference in mandible length between the two species, in each one the tip being just opposite the latero-apical angle of the clypeal margin. Color of the tarsi seems to be a reliable indication of the identity of each, being bright yellow in forbesii and dull brownish in athabascense. In the character of the gonostyli of the genital armature, however, there is apparent a distinct morphological difference, as given in the key, and it is this difference which suggests that these two very similar forms are distinct but closely related species.