Reprinted with permission of the American Entomological Society from:
LaBerge, W. E. 1973. A revision of the bees of the genus Andrena of the Western Hemisphere. Part VI. Subgenus Trachandrena. Transactions of the American Entomological Society 99: 235-371.
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Andrena rugosa is a distinctive eastern bee not closely related to any of the foregoing species. The female of rugosa is unlike any of the previously described females in the form of the facial fovea which is extremely narrow below and separated from the inner margin of the compound eye by more than twice the width of the fovea (at the level of the greatest separation from the eye). The female is also marked by the apical areas of terga 2-4 being long (as in miranda), the mesoscutum and scutellum being extremely coarsely punctate, and the vertex being short. The male of rugosa has the sixth sternum with the apical margin entire as in sigmundi but differs from sigmundi in the shorter first flagellar segment, the shorter vertex, and the simple hind tibial spur. The male of rugosa can also be recognized by the median mesoscutal line being distinctly indented.
FEMALE. MEASUREMENTS AND RATIOS. — N = 20; length, 8-10 mm; width, 2-3 mm; wing length, M = 3.82 ± 0.104 mm; FL/FW, M = 1.07 ± 0.005; FOVL/FOVW, M = 3.80 ± 0.043.
INTEGUMENTAL COLOR. — Black except as follows: mandible with apical fourth or third rufescent; flagellar segments 3-10 dark brown below; wing membranes hyaline, slightly yellowed, veins reddish-brown; tegula piceous except outer edge and summit; distitarsi often rufescent; hind tibial spurs testaceous to rufescent.
STRUCTURE. — Antennal scape length equal to first three and three-fourths flagellar segments or slightly longer; flagellar segments as in sigmundi but second segment often slightly shorter than broad. Eyes, malar space, mandible and galea as in sigmundi. Maxillary palpus as in sigmundi but segmental ratio about as 0.9:1.0:0.8:0.8:0.8:0.8. Labial palpus as in sigmundi but ratio about as 1.0:0.7:0.6:0.7. Labrum as in sigmundi. Clypeus with deep round punctures separated by half to almost one puncture width, margins of punctures depress surrounding integument slightly making puncture size somewhat obscure; without median impunctate line; surface shiny. Supraclypeal area rounded from side to side, with small round punctures separated mostly by more than half a puncture width, surface shiny. Genal area as in sigmundi. Vertex above lateral ocellus distinctly shorter than one ocellar diameter; with sparse punctures (one or two rows above lateral ocellus) and fine reticular shagreening dulling surface. Face above antennal fossae with distinct longitudinal rugae and interrugal punctures; surface moderately shiny. Facial fovea separated from lateral ocellus by about one ocellar diameter lower end extremely narrow, separated from inner eye margin by more than twice width of fovea at point of greatest separation; area between eye and lower part of fovea shiny, with a few small scattered punctures often arranged in an irregular row; lower end of fovea curves gently out towards inner eye margin.
Pronotum as in sigmundi but moderately shiny. Mesoscutum with large, deep, round punctures separated by half a puncture width or less, punctures more than twice diameter of those of center of vertex; surface dulled by fine dense tessellation. Scutellum similar but punctures more uniformly crowded. Metanotum similar but punctures smaller, extremely small and crowded laterally. Propodeum as in sigmundi but dorsal area outside of enclosure coarsely reticulorugose. Mesepisternum extremely coarsely rugatulopunctate with bottoms of large punctures dulled by coarse tessellation (so coarse as to appear to be fine punctures). Posterior hind tibial spur normal. Anterior femur with basal angle rounded (not as in quintiliformis). Wing venation as in sigmundi but second submarginal cell usually short.
Metasomal tergum 1 with apical depressed area twice as long as basal area or longer medially, basal area punctures sparse, small, separated mostly by one to three or four puncture widths; apical area punctures larger and separated mostly by half to one puncture width; surface shiny, lightly shagreened. Terga 2-4 with apical areas long, on second tergum equal in length to twice basal area medially or longer; punctures smaller on basal areas than on apical areas, generally separated by half to one puncture width, occasionally slightly sparser; surfaces, especially of apical areas extremely coarsely reticularly shagreened, shiny to moderately so. Pygidial plate and sterna as in sigmundi.
VESTITURE. — White to ochraceous, often dark ochraceous on thoracic dorsum and vertex; inner surfaces tarsi yellow. Distribution and form of hairs as in sigmundi except as follows: terga usually with apical pale fasciae absent or weak; dorsum of thorax with hairs relatively thick and blunt; fine facial foveal hairs white.
MALE. MEASUREMENTS AND RATIOS. — N = 20; length, 7-9 mm; width, 1.5-2.5 mm; wing length, M = 3.42 ± 0.230 mm; FL/FW, M = 1.12 ± 0.006; FS1/FS2, M = 0.68 ± 0.014.
INTEGUMENTAL COLOR. — Black with same exceptions as female but flagellar segments 2-11 dark brown below and terga apical areas often slightly rufescent.
STRUCTURE. — Antennae as in sigmundi but flagellar segment 1 always considerably shorter than segment 2 and quadrate. Eyes each about three and one-fourth times as long as broad, inner margins converging towards mandibles. Malar space, mandible and galea as in female (see sigmundi). Maxillary palpus as in sigmundi but segmental ratio about as 1.0:1.0:0.9:0.9:0.8:0.8. Labial palpus as in sigmundi but ratio about as 1.0:0.7:0.6:0.6. Labrum as in sigmundi. Clypeus as in female but punctures smaller. Supraclypeal area and vertex as in female. Face above antennal fossae as in female but rugae finer and closer together and punctures smaller, moderately dulled by fine shagreening. Genal area as in sigmundi.
Pronotum as in female. Mesoscutum with coarse shallow punctures separated mostly by half to one puncture width, sparser posteromedially; medial longitudinal line distinctly impressed drawing down integument on either side at least slightly. Scutellum similar to mesoscutum but punctures more crowded. Metanotum and propodeum as in female but propodeal dorsal area outside of enclosure often only moderately coarsely rugose. Mesepisternum as in female but large contiguous punctures slightly smaller. Posterior hind tibial spur normal. Wing venation as in female.
Metasomal tergum 1 with apical area indistinct, about as long as basal area; punctures as in female but apical area punctures usually sparser, often separated by one to two puncture widths; surface moderately dulled by reticular shagreening. Terga 2-5 with apical areas usually slightly shorter than basal areas medially and never longer; with fine punctures separated mostly by one to two puncture widths; surfaces at least moderately dulled by reticular shagreening which is finer and denser near bases of terga. Sterna as in sigmundi. Terminalia as in sigmundi; see figures 50-51.
VESTITURE. — Generally white to pale ochraceous; terga 2-4 usually with weak apical fasciae, broadly interrupted on tergum 2 and often narrowly so on tergum 3; basal areas of terga as in sigmundi.
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 9 mm.; face slightly longer than broad; clypeus slightly convex, projecting nearly one-half below suborbital line, shining, punctures deep and distinct, rather fine, well separated but not sparse, without a distinct, median, impunctate line; facial foveae quite broad above, occupying about three-fourths of space between eyes and ocelli, covered with whitish tomentum, very abruptly and narrowly constricted below, constricted portion widely removed from eye margin and about one-fourth width of the upper part; space between margin of vertex and lateral ocelli subequal to their diameter; cheeks slightly broader than eyes, rounded posteriorly, rather dull, finely and closely punctate, punctures becoming somewhat sparse above on lateral areas of vertex; malar space distinct, but rather short; basal segment of flagellum slightly shorter than 2nd and 3rd combined; process of labrum about twice as broad as long, somewhat narrowed to the rather broadly truncate apical margin; pubescence of head, thorax and legs whitish, becoming pale ochraceous above and on the more apical portions of legs, that on dorsum of thorax rather short, quite dense, partially obscuring surface; punctures of scutum and scutellum coarse, deep and uniformly close; pleura coarsely rugoso-punctate, becoming relatively smooth posteriorly; dorsal area of propodeum oblique, triangle quite coarsely and evenly striate; propodeal corbicula short, rather dense, without a distinct anterior fringe, very pale ochraceous; trochanteral floccus rather long, whitish; hind tibiae broadened apically, apex about twice width of basitarsi, scopa quite dense, hairs of moderate length, simple, entirely whitish; mid basitarsi subequal to their tibiae in width, the fore basitarsi somewhat narrower; 2nd submarginal cell considerably shorter than 3rd, receiving 1st recurrent about one-fourth from apex; abdominal terga somewhat shining, deeply, distinctly but rather finely punctate, punctures close along the narrow basal portions, somewhat more widely separated, but yet not sparse, on the broad, apical, impressed areas, these occupying medially about three-fourths length of disc, becoming narrowly reddish-hyaline along rims, discal pubescence very sparse, short, suberect, apparently entirely pale, terga 2-4 with white, apical fasciae evident at extreme sides, but widely interrupted medially, tergum 5 with a golden-brownish, apical fimbria.
MALE. — Length 9 mm.; face slightly longer than broad; clypeus rather strongly convex and protuberant, projecting nearly one-half below suborbital line, shining between deep, distinct, rather close and coarse punctures; space between margin of vertex and lateral ocelli subequal to their diameter; cheeks slightly broader than eyes, rounded posteriorly, very obscurely and finely punctate; malar space distinct but short; basal segment of flagellum considerably shorter than 2nd and following segments, only slightly longer than apex is broad; process of labrum about twice as broad as long, narrowed to the rather broadly truncate apical margin: mandibles with a distinct, inner, subapical tooth, overlapping nearly one-third; pubescence of head, thorax and legs pale ochraceous; scutum and scutellum dull, punctures quite deep, close and rather coarse; pleura rather coarsely rugosopunctate; dorsal area of propodeum oblique, triangle rather coarsely and evenly striate; basitarsi slender and elongate, considerably narrower than their respective tibiae; 2nd submarginal cell considerably shorter than 3rd, receiving 1st recurrent about one-fourth from apex; abdominal terga rather dull, punctures quite fine and close, but deep and distinct, apical impressed areas shallow, occupying medially about one-half length of disc, punctures finer and more obscure than on the basal portions, becoming gradually reddish-hyaline toward rims, discal pubescence very short, thin, erect, entirely pale, terga 2-4 with very thin and obscure, whitish, apical fasciae, rather broadly interrupted on tergum 2; apical portion of sternum 8 slender and elongate, apex slightly expanded, rather abruptly truncate, clothed beneath with rather long, pale pubescence; penis valves slender apically, only very slightly dilated basally, quite deeply excavated laterally, gonocoxites abruptly dilated apically, forming subtriangular, concave lobes, which are slightly produced apically, gonocoxal lobes strongly produced, slender and acute, attaining the apical lobes (similar to hippotes, fig. 37).
DISTRIBUTION. — Minnesota to the New England states and Nova Scotia, south to North Carolina and Georgia; April to July.
FLOWER RECORDS. — Malus, Rubus, Spiraea and Viburnum. Robertson (1929) records this species on the following plant genera: Acer, Amelanchier, Claytonia, Cornus, Crataegus, Dentaria, Dirca, Erigenia, Hepatica, Heracleum, Isopyrum, Prunus, Ptelea, Rhus, Ribes, Salix, Sanicula and Zanthoxylum. It is also recorded on Taraxacum by Brittain and Newton (1933).
In his 1907 key, Viereck distinguished between rugosa and paenerugosa by the presence or absence of abdominal fasciae. Apparently this is not a valid distinction, for Robertson described rugosa as lacking fasciae except at extreme sides. A homotype specimen which the writer compared with the lectotype lacks even this degree of their development. In our opinion, this is a variable character, occasional individuals showing some degree of development of the latero-apical fasciae.