Reprinted with permission of the American Entomological Society from:
LaBerge, W. E., Ribble, D. W. 1972. A revision of the bees of the genus Andrena of the Western Hemisphere. Part V: Gonandrena, Geissandrena, Parandrena, Pelicandrena. Transactions of the American Entomological Society 98: 271-358.
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Andrena fragilis is a small species found associated with the eastern and northern hardwood forests. Both sexes of fragilis are marked by the keeled genal area, the shiny metanotum and shiny abdomen. The male of fragilis can be separated from that of other species of Gonandrena by the free clypeal apical margin being emarginate with a broad V-shaped emargination (especially evident when viewed from below), flagellar segments 2 or 3 to 11 red to yellow below, and sternum 2 lacking a subapical fimbria (sterna 3-5 with weak fimbriae). The female of fragilis can be readily recognized by its large, almost rectangular labral process. Occasionally the labral process is slightly narrower at the base than subapically and it is usually depressed medially. The flagellar segments of the female are paler than in other species, as in the male.
FEMALE. MEASUREMENTS AND RATIOS: N = 20; length, 9-9 mm; width, 2.0-2.5 mm; wing length, M = 3.21 ± 0.148 mm; FL/FW, M = 0,97 ± 0.005; FOVL/FOVW, M = 3.99 ± 0.065.
INTEGUMENTAL COLOR. — Black except as follows: mandible with apical half rufescent; flagellar segments 3-10 dark red to yellow below; wing membranes hyaline, slightly infumate, veins dark reddish-brown; tegulae rufescent; terga 1-5 with apical areas usually hyaline, somewhat rufescent near basal areas; legs slightly rufescent; tibial spurs yellow.
STRUCTURE. — Antennal scape length equal to first four and one-half flagellar segments; segment 1 slightly longer than or equal to segments 2 plus 3; segment 2 about equal in length to 3, each broader than long and shorter than 4; segments 4-6 or 7 slightly broader than long, 8 and 9 quadrate. Eyes each about 3.4 times as long as broad, inner margins converging slightly towards mandibles. Mandible moderately long, at rest surpassing mid-labrum by one-fifth length of mandible, with inner subapical tooth. Galea pointed, broad, shiny, surface unshagreened or only delicately so. Labial palpus with first segment terete, long, curved segmental ratio about as 1.0:0.5:0.5:0.6. Maxillary palpus surpassing galea by more than last two segments, segmental ratio about as 1.0:1.0:0.8:0.8:0.6:0.6. Labral process large, rectangular with rounded apical corners and depressed median surface, often slightly narrower at base than greatest width; labrum below process transversely sulcate, shiny. Clypeus rounded from side to side, distinctly punctate with small round punctures separated mostly by half to one puncture width, impunctate or sparsely punctate along midline, surface moderately dulled by fine reticular shagreening. Supraclypeal area dulled by minute sparse punctures and reticular shagreening. Face above antennal fossae with weak longitudinal rugulae, interrugal punctures and fine shagreening, moderately shiny. Facial fovea narrow, separated from lateral ocellus by one ocellar diameter, extending down to about level of lower margins antennal fossae. Vertex above lateral ocellus as high as one ocellar diameter or slightly less, moderately shiny. Genal area broad, almost twice as broad as eye in profile, with complete posterior carina; surface shiny with sparse minute punctures and fine shagreening.
Pronotum with 4 or 5 fine dorsoventral rugulae extending down from angle; sparsely punctate, finely shagreened. Mesoscutum moderately shiny to dull, with small round punctures separated mostly by two to three puncture widths or more, surface finely tessellate. Scutellum shiny, with sparse punctures, devoid of microsculpture. Propodeum with dorsal area, triangular with coarse, short, anastomizing rugulae; dorsolateral and posterior surfaces moderately finely rugatulopunctate, finely tessellate; lateral surfaces opaque, finely but deeply reticularly shagreened, with several piliferous punctures in posterior half. Mesepisternum rounded below, moderately dulled by scattered punctures and reticular shagreening. Wing with pterostigma moderately large, broader than from inner margin prestigma to wing margin; vein 1st m-cu meets second submarginal cell in outer fourth or fifth; second submarginal cell small, quadrate or slightly shorter anteriorly.
Metasomal tergum 1 shiny, with extremely sparse and minute punctures, surface unshagreened. Tergum 2 with basal area punctures round, separated by one to two puncture widths or more except in impunctate narrow band just basad of apical area; apical area punctate as in basal area but punctures slightly smaller, surfaces shiny, unshagreened or delicately so. Terga 3-4 similar but punctures progressively sparser and shagreening denser. Pygidial plate V-shaped with rounded apex; with raised, roughened, internal triangle coming to a narrow, sharp point. Sterna 2-5 with sparse punctures separated mostly by 2-5 puncture widths except in narrow apical areas, surfaces shiny, unshagreened or delicately so.
VESTITURE. — Generally white, sparse, inner surfaces hind tarsi yellow to red and last two terga brownish. Thoracic dorsum with hairs mostly short, plumose, sparse but hiding surface, a few long, more erect hairs present; propodeal corbicula incomplete anteriorly with several long simple internal hairs; tibial scopal hairs long, simple, sparse, not hiding surface. Metasomal terga 2-4 with narrow, complete, apical white fasciae, thinner medially, often incomplete medially on tergum 2, less often so on tergum 3; sterna without subapical fimbriae.
MALE. MEASUREMENTS AND RATIOS: N = 20; length, 6-9 mm; width, 1.5-2.5 mm; wing length, M = 2.83 ± 0.166 mm; FL/FW, M = 0.99 ± 0.008; FS1/FS2, M = 1.88 ± 0.031.
INTEGUMENTAL COLOR. — Black with same exceptions as in female but rufescent tints frequently present in genal areas and sterna; tegulae more hyaline and with less color than in female.
STRUCTURE. — Antennae of moderate length, reaching metanotum in repose; scape length about equal to first three flagellar segments; flagellar segment 1 longer than segments 2 plus 3, segment 2 shorter than 3 and about as broad as long or broader, segments 3-11 longer than broad. Eyes each about two and three-fourths times as long as broad, inner margins parallel or converging slightly towards mandibles. Galea as in female. Mandible long, decussate. Labial palpus as in female but ratio about 1.0:0.7:0.7:0.7. Maxillary palpus as in female but ratio about 1.0:1.0:0.6:0.6:0.5:0.6. Labral process 'mail, rounded to trapezoidal, labrum apical to process not deeply sulcate. Clypeus much flattened with small round punctures separated mostly by 3 to 5 puncture widths or more, surface moderately dulled by fine tessellation; apical free margin long, with broadly V-shaped emargination. Supraclypeal area and face above antennal fossae as in female. Genal area flat with prominent lower angle and prominent posterior carina the entire length, surface with scattered minute punctures and fine tessellation.
Pronotum with strong dorsoventral ridge behind which surface shiny, unshagreened, elsewhere dulled by minute punctures and dense reticular shagreening. Mesoscutum, scutellum and propodeum as in female except as follows: propodeal dorsal enclosure slightly less coarsely rugulose and lateral surface more irregularly roughened. Wing venation as in female.
Metasomal sculpturing as in female. Sternum 6 not or only weakly reflexed apically, with broad U-shaped apical emargination.
Terminalia as in figures 10-14; note the following: gonocoxite with dorsal lobes long and turned outwards apically; penis valves with large dorsal and ventral lamellae near base (ventral lamellae larger than dorsal); sternum 7 distinctly bidentate apically; sternum 8 with apex slightly broader than neck region.
VESTITURE. — Generally as in female but hairs less abundant, longer on thoracic dorsum, lacking pollen-collecting hairs and sterna 2-5 without subapical fimbriae or these present but weak only on sterna 3-5.
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 mm.; clypeus very slightly convex, projecting about one-third below suborbital line, rather dull, finely punctate, punctures well separated medially, but becoming quite close at extreme sides, with an indefinite, median, impunctate line; facial foveae narrow, occupying above hardly half of space between eyes and ocelli, covered with whitish tomentum; space between margin of vertex and lateral ocelli subequal to their diameter; cheeks broader than eyes, rounded posteriorly, the posterior margin conspicuously carinate, surface shining, minutely and rather closely punctate; malar space very short; basal segment of flagellum subequal to 2nd and 3rd combined; process of labrum quadrate, nearly as long as broad, rather large; pubescence of head, thorax and legs whitish, faintly tinged with yellowish, thoracic integument dull, punctures of scutum fine, shallow, well separated even anteriorly, becoming somewhat more sparse posteriorly, where surface is somewhat shining, those on scutellum minute, scattered and irregular, sparse on each side of a more closely punctate median line, surface polished; pleura more densely tessellate, subrugose above; dorsal area of propodeum nearly horizontal, rather broad, triangle finely rugoso-striate; propodeal corbicula poorly developed, thin, pale ochraceous, without an anterior fringe; trochanteral floccus rather well developed, white; hind tibiae very slender, hardly exceeding the basitarsi in width, scopa thin, of rather elongate simple hairs, entirely white; front and middle basitarsi slightly narrower than their respective tibiae; 2nd submarginal cell much shorter than 3rd, receiving 1st recurrent at outer third; abdominal terga smooth and shining, basal tergum very sparsely and minutely punctate, surface polished, punctures of 2nd and following terga fine, close and distinct, becoming more sparse toward apical impressed area on tergum 2, impressed areas shallow, occupying about one-third median length of disc, becoming quite broadly yellowish-hyaline along rims, discal pubescence extremely sparse, short, suberect, entirely pale, terga 2-4 with rather dense, white, apical fasciae, broadly interrupted on tergum 2, more narrowly so on 3, tergum 5 with a brownish-ochraceous, apical fimbria.
MALE — Length 6-7 mm.; head broader than thorax; clypeus broad and flat, markedly narrowed apically, projecting nearly one-half below suborbital line, somewhat shining, finely punctate, punctures well separated medially, becoming rather close at extreme sides; space between margin of vertex and lateral ocelli subequal to their diameter; cheeks broader than eyes, posterior margin conspicuously carinate, more or less parallel with eye margin, surface somewhat shining, punctures exceedingly minute and rather close; malar space exceedingly short; basal segment of flagellum slightly shorter than 2nd and 3rd combined; process of labrum obscured by the overhanging margin of clypeus, tip visible, quite narrow; mandibles rather elongate, inner subapical tooth located about one-third of length from tip, overlapping fully one-third; pubescence of head, thorax and legs entirely whitish, slightly tinged with yellowish; thoracic integument dull, punctures of scutum very fine, shallow and obscure, well separated over most of disc, but becoming somewhat more sparse posteriorly, those on scutellum very minute and obscure, irregularly scattered, the surface shining; pleura finely roughened or subrugose; dorsal area of propodeum oblique, triangle finely rugosostriate; basitarsi more or less testaceous, slender and elongate, considerably narrower than their respective tibiae; 2nd submarginal cell much shorter than 3rd, receiving 1st recurrent about one-fourth from apex; abdominal terga smooth, shining, punctures exceedingly minute and obscure, rather close laterally, apical impressed areas very shallow, rather narrow, almost completely yellowish-hyaline, discal pubescence exceedingly short, sparse and obscure, apparently entirely pale, apical white fasciae very thin and obscure, partially developed toward sides of terga; apical portion of sternum 8 rather short, gradually broadened toward base, apex truncate; penis valves slender apically, broadly dilated toward base, where they are deeply grooved or excavated laterally, gonocoxites rather slender, gradually dilated toward apex, the resulting lobes rather narrowly rounded apically, gonocoxal lobes strongly produced, narrowly rounded apically.
DISTRIBUTION — Eastern Canada and the entire Eastern United States, with the possible exception of Florida, ranging west to Colorado and New Mexico; May to July.
FLOWER RECORDS — Ceanothus, Cornus, Hydrangea, Svida and Viburnum. Recorded by Robertson (1929, as A. platyparia) on Aruncus, Cryptotaenia, Pastinaca, Ptelea and Rhus.