Reprinted with permission of the University of Nebraska State Museum from:
LaBerge, W. E. 1967. A revision of the bees of the genus Andrena of the Western Hemisphere. Part I. Callandrena (Hymenoptera: Andrenidae). Bulletin of the University of Nebraska State Museum 7: 1-316.
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This is a small bee ranging from southern Canada to North Carolina and from Minnesota to the eastern seaboard. Both sexes of A. placata are very similar to A. simplex. The female of placata can be distinguished from that of simplex by the third flagellar segment being slightly longer than the second, the facial foveae extending down to the level of the lower margins of the antennal fossae, and the metasomal terga being shinier and finely but distinctly punctate. The male of placata can be distinguished from that of simplex by the third flagellar segment being distinctly longer than the second and the metasomal terga being shinier and more distinctly punctate. Mitchell (1960) described only the male of this species and had confused the females with those of simplex. Previous authors had confused both sexes of placata with those of simplex. Therefore, at least some of the references given under simplex should refer to placata. It is not possible, however, to disentangle the misidentifications resulting from this confusion.
FEMALE. MEASUREMENTS AND RATIOS. — N = 20; length, 9.0-10.0 mm; width 2.5-3.5 mm; wing length, M = 3.25 ± 0.025 mm; FL/FW, M = 0.95 ± 0.004; FOVL/FOVW, M = 2.42 ± 0.039.
INTEGUMENTAL COLOR. — Black except as follows: mandible rufescent in apical half; wing membrane moderately infumate, veins black to dark brown; terga with apices extremely narrowly hyaline, slightly reddened posterior to hyaline apices; sterna with apices hyaline, yellow, slightly rufescent basally; distitarsi often rufescent; tibial spurs yellow.
STRUCTURE. — Scape as in simplex; flagellar segment 1 slightly longer than segments 2 plus 3, segment 3 distinctly longer than segment 2, shorter than segments 4-9. Eye about three and one-half times as long as broad, inner margins strongly converging towards mandibles. Malar space, mandible and galea as in simplex. Maxillary palpus reaching tips of galeae or very slightly beyond, segments un ratio of about 0.7:1.0:0.5:0.5:0.5:0.6. Labial palpus as in simplex but segments in ratio of about 1.6:0.8:0.7:0.8. Clypeus, supraclypeal area, and genal area as in simplex but genal area usually slightly broader than eye in profile. Vertex as in simplex but above lateral ocellus equals about one ocellar diameter. Face above antennal as in simplex. Facial fovea relatively deep, extending down to level of lower margin of antennal fossa or almost so, upper end broad, separated from lateral ocellus by about half of an ocellar diameter, lower end rounded.
Pronotum, mesoscutum, scutellum, and metanotum as in simplex. Propodeum with enclosure with sides straight, surface finely areolate, moderately shiny; dorsolateral and posterior surfaces with small punctures separated by one to three puncture widths, surface dulled by reticular shagreening; corbicular surface moderately shiny, with small punctures scattered throughout, with coarse reticular shagreening. Metepisternum and mesepisternum as in simplex. Middle basitarsus broadened medially, sides evenly rounded, distinctly broader than hind basitarsus. Tibial spurs and claws normal. Front wing with three submarginal cells, vein 1st m-cu meets second submarginal cell at about two-thirds distance from base of cell; pterostigma usually about as broad as from inner margin prestigma to wing margin, occasionally slightly broader.
Metasomal terga 1-5 with small, round, distinct punctures, sparse on tergum 1, on terga 2-4 separated mostly by two to three puncture widths, surfaces shiny to moderately shiny, with fine reticular shagreening. Pygidia1 plate strongly V-shaped, apex. rather sharp. Sterna 2-5 with crowded punctures near apical hyaline areas, punctures separated mostly by one puncture width next to hyaline area, becoming sparser basally, surfaces moderately dulled by coarse reticular shagreening.
VESTITURE. — As in simplex except as follows: often apex of clypeus and labrum with brown hair, vertex often with a few brown hairs, mesoscutum and scutellum often with brown hairs medially, terga 5 and G with dark brown hairs, tarsi usually with brown hails, fore and middle tibiae usually with brown hairs, scopal hairs washed with brown posteriorly. Pollen collecting hairs as in simplex.
MALE. MEASUREMENTS AND RATIOS. — N = 20; length, 8.0-10.0 mm; width, 2.0-3.0 mm; wing length, M = 2.91 ± 0.112 mm; FL/FW, M = 0.99 ± 0.006; FS1/FS2, M = 1.88 ± 0.035.
INTEGUMENTAL COLOR. — As in female except as follows: clypeus yellow except brown apical margin and dark spots mesad and below tentorial pits; flagellar segments 3-11 slightly reddened below; tergal apices with hyaline areas often slightly broader.
STRUCTURE. — Antennae short, extending to posterior margin of tegulae in repose; scape slightly longer than flagellar segments 1-2, flagellar segment 1 distinctly shorter or no longer than segments 2; plus 3, segment 3 distinctly longer than segment 2 and subequal to 4. Eye about three and one-fourth times as long as broad or slightly, longer, inner margins strongly converging towards mandibles. Malar space, mandible, and galea as in female. Maxillary palpus as in female but segments in ratio of about 0.9:1.0:0.7:0.7:0.6:0.8. Labial palpus as in female but ratio of about 1.4:0.7:0.5:0.7. Labral process small, bidentate. Clypeus and supraclypeal area as in female but clypeal punctures slightly more distinct. Genal area, vertex and face above antennal fossae as in female.
Sculpturing of thorax as in female except as follows: mesoscutum and scutellum with medial areas shinier, punctures sparser. Wings, claws, and tibial spurs as in female. Terga 1-5 as in female terga 1-4, often shinier, shagreening finer and reticulations coarser and puncture more distinct, Tergum 7 with median longitudinal glabrous area indistinct. Sterna 2-5 as in female but punctures sparser and surfaces shinier. Sternum 6 with apical margin only slightly reflexed, broadly and shallowly emarginate medially.
Genitalia and sterna 7 and 8 (Figs. 139-143) similar to those of simplex but note following: gonoforceps with inner-dorsal ridge not enlarged; penis valves broad near base; dorsal lobe gonocoxites longer; sternum 7 with apicolateral lobes shorter; sternum 8 with tip broader and often extremely shallowly emarginate apically.
VESTITURE. — In general white; terga 1-5 with weak apical hair bands, that on tergum 1 interrupted medially by more than half width of tergum, that on tergum 2 interrupted medially by about halt width of tergum; sternal hairs forming distinct apical bands of relatively short suberect white hairs just basad of apical hyaline areas; inner surfaces tarsi pale yellow.
TYPE MATERIAL. — The holotype (NCSU) male from Needham, Massachusetts, August 13, 1936, was collected by T. B. Mitchell.
DISTRIBUTION. — Andrena placata ranges from Quebec and Ontario south to North Carolina and west through Ohio and Michigan to Minnesota (Fig. 9). This species has been taken from August 2nd through October 10th but chiefly during August and early September. A total of 237 females and 67 males have been examined in addition to the holotype. The localities of these are listed below. CONNECTICUT: Colebrook; New Haven; Stafford; Stores. DISTRICT OF COLUMBIA: Anacostia. IOWA: Ledges State Park. ILLINOIS: McHenry. MAINE: Biddleford Pool; Casco Bay; Kezar Falls; Seco. MARYLAND: Chesapeake Beach; Glen Echo. MASSACHUSETTS: Arlington; Boston; Brookline; Forest Hills; Framingham; Holliston; Hopkinton; Waltham. MICHIGAN: Ocama Co.; Cheboygan Co. MINNESOTA: Cannon Falls; Fort polling; Hastings; Hennepin Co.; Pine River; Ramsey Co.; St. Anthony Park; St. Paul. NEW HAMPSHIRE: Alton Bay, Belknap Co.; Belknap Co.; Conway; Carrol Co.; Farmington; Grafton Co.; Meredith Center; New Durham; Pelham; Webster. NEW JERSEY: Big Timber Creek; Camden Co.; Cape May; Clementon; Clifton; Englewood; Lakehurst; Lucaston; Marlton; Montclair; Montvale; Moorestown; New Albany; New Egypt; Ongs Hal (2 miles E.); Ramsey; Riverton; Union; Watchung Reservation, Union Co.; Westfield; Whitesvale. NEW YORK: Amagon; Bedford; Cold Spring Harbor, Long Island; Copake Falls; Flatbush, Long Island; Geneva; Hartsdale; Ithaca; Lynbrook; Moshalu; New Rochell; New York City; Nyack; Poundridge; Rochester; Suffolk Co.; Tappan; Tompkins Co.; Tuxedo; White Plains. NORTH CAROLINA: Black Mountains (valley of); Blowing Rock; Marion; New River; Raleigh; Swannanoa; Washington Co. OHIO: Stark Co. PENNSYLVANIA: Fern Rock; Milford. VERMONT: Bennington Co.; Montpelier; Lyndon. VIRGINIA: Camp Perry; Hunting Creek. WISCONSIN: Menomonie; Milwaukee; Oconto Falls. Canada. ONTARIO: Ollawa; Spencerville; Toronto. QUEBEC: La Trappe.
REMARKS. — A. placata evidently hybridizes occasionally throughout its range with the closely related A. simplex. The hybrid specimens seem to be exactly intermediate between the two species, even to details of the male terminalia, therefore, backcrossing must occur infrequently, if at all. Several of the hybrid females had been gathering pollen when killed, thus probably had mated and were nesting. If these females mated with either parent or with hybrid males, presumably their eggs were infertile, as no second general ion hybrids were discovered among the aggregate (318 specimens available of the two species. The collection data of the 22 female and 25 male hybrids are given below.
CONNECTICUT: Hartford. 1 female, August 29, 1897, on Solidago. MARYLAND: Laurel. 1 female, September 17, 1916, J. Silver. Plummers Island. 1 male, September 16, 1906, A. K. Fisher. 1 female, 1 male, from the T. Pergande collection. MASSACHUSETTS: Greenfield. 1 female, 1 male, August 11, 1916, I. N. Gabrielson. NEW JERSEY: Clementon. 1 female, October 4, 1904. Englewood. 1 female, October 7, 1942, on Solidago, C. D. Michener. NORTH CAROLINA: Bryson City. 1 female, September 22, 1922, T. B. Mitchell; 2 females, 1 male, September 7, 1923, on Solidago, J. C. Crawford; 1 male, September 25, 1923, on Aster ericoides, J. C. Crawford; 2 females, 1 male, September 26, 1923, on Aster paniculatus, J. C. Crawford. Raleigh. 1 female, late September, 1921, T. B. Mitchell. VIRGINIA: Black Pond. 1 female, September 13, 1916, H. L. Viereck. Chain Bridge. 1 male, September 18, 1921, J. R. Malloch. Four-mile Run. 1 male, October 8, 1916, on Aster, W. L. McAtee, J. Hunter. 5 males, September 12, 1918, R. A. Cushman. Hunting Creek, 2 males, September 23, 1917, on Aster, W. L. McAtee.
FLORAL RECORDS. — Andrena placata is an oligolege of the composite genus Solidago. It has been collected on other flowers only a few times. Out of 37 collections (93 females and 20 males), 31 collections (88 females, 19 males) were taken from flowers of the genus Solidago. Plants from which this species has been collected are listed below.
Aster sp., A. lateriflorum, A. macrophyllum, Eupatorium serotinum, Fagopyrum esculentum, Solidago sp.
Reprinted with permission from: Mitchell, T.B. 1960. Bees of the Eastern United States. North Carolina Agricultural Experiment Station Technical Bulletin No. 141.
MALE — Length 9 mm.; clypeus slightly convex, projecting but very slightly below suborbital line, yellow except for two small black spots and the blackish apical rim, smooth and shining, punctures fine, well separated medially, becoming quite close at extreme sides; space between margin of vertex and lateral ocelli very slightly greater than their diameter; cheeks very slightly broader than eyes, rounded posteriorly, rather dull, punctures distinctly separated, rather obscure, becoming very minute along eye margin, more coarse posteriorly; malar space extremely short; basal segment of flagellum nearly twice as long as the very short 2nd segment, but slightly shorter than 2nd and 3rd combined; process of labrum rather short, quite broad, slightly narrowed to the deeply emarginate apex; mandibles of moderate length, with a distinct, inner, subapical tooth, overlapping about one-third; pubescence of head, thorax and legs entirely whitish; thoracic integument dull, rather densely tessellate, punctures of scutum shallow, rather close, but distinctly separated anteriorly, becoming more sparse and surface more shining posteriorly, those on scutellum scattered, very shallow and obscure, surface somewhat shining, pleura roughened or subrugose above, with some very obscure, barely evident punctures anteriorly; dorsal area of propodeum more oblique, rather narrow, triangle obscurely subrugose toward basal margin; basitarsi slender and elongate. considerably narrower than their respective tibiae; wings faintly infuscated apically, 2nd submarginal cell considerably shorter than 3rd, receiving 1st recurrent just beyond middle; abdominal terga smooth, shining, minutely punctate, the punctures well separated but not sparse, exceedingly minute and obscure on basal tergum, apical impressed areas shallow, quite narrow, discal pubescence extremely short, thin, erect and fuscous, terga 1-4 with thin, narrow, white, apical fasciae evident laterally, that on tergum 4 nearly entire; apical margin of sternum 6 quite strongly reflexed; apical portion of sternum 8 slender and elongate, sides nearly parallel, apex somewhat dilated, broadly truncate, clothed beneath with thin, pale pubescence; penis valves slender apically, dilated basally, somewhat excavated or grooved laterally toward base beneath, gonocoxites gradually and slightly dilated toward apex, gonocoxal lobes quite strongly produced, narrowly rounded.
TYPES - Holotype: Male, Needham, Mass., Aug. 13, 1936 (T. B. Mitchell). Paratypes: MASSACHUSETTS: 2 MM, Needham, Sept 3, 1927; 1 M, Needham, Aug. 21, 1926 (all Mitchell); 1 M, Middlesex Falls, Aug. 19, 1911 (W. M. Wheeler). CONNECTICUT: 2 MM, Colebrook, Aug., 1918, and Aug. 15, 1919 (Wheeler). MINNESOTA: 1 M, St. Paul, Aug. 5, 1921 (Wm. E. Hoffman). MICHIGAN: 4 MM, Oceana Co., Aug. 15, 1945; 4 MM, Oceana Co., Aug. 10, 1946; 2 MM, Ionia Co., July 24, 1940; 1 M, Bay Co., Aug. 25, 1946; 1 M, Midland Co., Aug. 5, 1951 (all R. R. Dreisbach); 1 M, Gladwin Co., Aug. 3, 1957 (R. & K. Dreisbach). VIRGINIA: 1 M, Camp Peary, Sept. 7, 1943 (R. M. & C. E. Bohart).
These paratypes are located at the Museum of Comparative Zoology, the University of Minnesota, in collections of R. R. Dreisbach and R. M. Bohart, and in the author's collection.
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