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Andrena cragini Cockerell, 1899
Life   Insecta   Hymenoptera   Apoidea   Andrenidae   Andrena
Subgenus: Rhacandrena



Andrena cragini, F, Back, Pennington Co, SD
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Andrena cragini, F, Back, Pennington Co, SD

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Andrena cragini, F, Face, Pennington Co, SD
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Andrena cragini, F, Face, Pennington Co, SD
Andrena cragini, F, Side, Pennington Co, SD
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Andrena cragini, F, Side, Pennington Co, SD

Andrena cragini, face
Smithsonian Institution, Entomology Department · 1
Andrena cragini, face
Andrena cragini, side
Smithsonian Institution, Entomology Department · 1
Andrena cragini, side

Andrena cragini, top
Smithsonian Institution, Entomology Department · 1
Andrena cragini, top

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Andrena cragina – A small vernal bee that specializes on Amorpha flowers and flies in May and June. It is separated from other Rhacandrena by the more pitted clypeus and longer galea. The male is noted for having a yellow clypeus as well as yellow parocular areas.

Overview
Reprinted with permission of the American Entomological Society from: LaBerge, W. E. 1977. A revision of the bees of the genus Andrena of the Western Hemisphere. Part VIII. Subgenera Thysandrena, Dasyandrena, Psammandrena, Rhacandrena, Euandrena, Oxyandrena. Transactions of the American Entomological Society 103: 1-144.

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Andrena cragini is a small species of the Great Plains region which is seemingly restricted to species of leadplant (Amorpha). It can be distinguished from the other species of Rhacandrena in both sexes by the longer, more punctate clypeus, the longer, spear-shaped galea and the relatively short maxillary palpus (short in relation to the galea). The male usually has yellow parocular maculae as well as a yellow clypeus. The female is described below for the first time.

FEMALE. MEASUREMENTS AND RATIOS. N = 20; length, 9-11; mm width, 2-3 mm; wing length, M = 3.21 0.139 mm; FL/FW, M = 1.16 0.005; FOVL/FOVW, M = 4.05 0.051.

INTEGUMENTAL COLOR. Black except as follows: mandible with about apical third rufescent; flagellum below dark reddish-brown to red; tegulae testaceous; wing membrane hyaline, veins reddish-brown to brown; metasomal terga 2-4 narrowly hyaline apically; distitarsi and hind basitarsi usually rufescent.

STRUCTURE. Antennal scape length equals first four flagellar segments or slightly less; flagellar segment 1 about as long as segments 2 plus 3, segments 2 and 3 subequal in length, broader than long, segments 4-9 about as long as broad. Eyes each about four times as long as broad, inner margins parallel. Mandible and malar area as in brevipalpis. Galea long, broad, outer margin straight or gently convex in apical half or more, apex rounded; surface dulled by fine tessellation. Maxillary palpus not much longer than galea when both extended forward, segmental ratio about as 1.0:1.0:0.9:0.7:0.6:0.6. Labial palpus as in brevipalpis but ratio about as 1.0:0.6:0.5:0.5. Labral process entire, large, rounded apically, about one and one-half times as broad at base as long; labrum below process with one weak median crista or cristae absent. Clypeus with small round punctures separated mostly by half to one puncture width, without median impunctate line; surface shiny medially, shagreened basally and laterally to entirely shagreened but moderately shiny. Supraclypeal area dulled by fine irregularly longitudinal rugulae and minute punctures. Genal area in profile about as broad as eye, surface dulled by reticular shagreening and minute punctures except in narrow zone near eye margin; lower surface dulled by coarse shagreening. Vertex above lateral ocellus equal to about one ocellar diameter; dulled by coarse tessellation and small punctures without impressed line behind lateral ocellus but present immediately behind median ocellus. Face above antennal fossae with abundant elongate punctures and fine longitudinal rugulae. Facial fovea as in brevipalpis.

Pronotum normal, moderately dulled by fine reticular shagreening, diagonal suture visible only posteriorly. Mesoscutum with small round punctures separated mostly by half to two puncture widths, surface dulled by fine tessellation. Scutellum similar but shinier. Metanotum opaque, densely punctate, tessellate. Propodeum with dorsal enclosure with irregular short rugae basally, coarsely tessellate, irregularly and shallowly areolate medially (merely roughened); dorsal surface outside of enclosure and posterior surface dulled by dense coarse tessellation and obscure punctures; lateral surface dull, tessellate with scattered piliferous punctures. Mesepisternum dull, smoothly tessellate with scattered obscure punctures. Wing venation as in brevipalpis but vein 1st m-cu meets second submarginal cell near middle of cell.

Metasomal tergum 1 with small round punctures separated mostly by one puncture width on disc, more crowded in apical area, surface moderately shiny, delicately shagreened. Terga 2-4 similar but discs with punctures slightly sparser and shagreening often coarse. Pygidial plate V-shaped with bluntly rounded apex, internal triangular area present. Sterna with narrow apical hyaline rims impunctate, discs with punctures separated by half to two puncture widths becoming sparser near bases; surfaces dulled by reticular shagreening.

VESTITURE. Generally ochraceous except terga 5 and 6 golden-brown at least medially, basitibial plate brown and inner surfaces tarsi pale yellow. Form and distribution of hairs as in brevipalpis but tibial scopal hairs more dense.

MALE. MEASUREMENTS AND RATIOS. N = 18; length, 7-9 mm; width, 1.5-2.0 mm; wing length, M = 3.05 0.419 mm; FL/FW, M (17) = 1.21 0.007; FS1/FS2, M(17) = 1.60 0.021.

INTEGUMENTAL COLOR. Black except as follows: mandible with apical third to half rufescent; clypeus yellow except brown apical margin and dark maculae below tentorial pits; parocular areas usually with small yellow; oval maculae (only one specimen lacks maculae); flagellar segments 2-11 yellow to reddish-brown below; tegulae testaceous; wing membranes hyaline, veins reddish-brown; metasomal terga with apical areas hyaline, slightly reddened at bases; sterna 2-5 narrowly hyaline apically; distitarsi reddish-brown.

STRUCTURE. Antennae short, in repose not exceeding scutellum; scape length equals about first two and one-third to two and one-half flagellar segments; flagellar segment 1 about one and one-half times as long as segment 2 or more and longer than segment 3, segment 3 longer than broad and longer than segments 2, segments 3-10 subequal in length. Eyes each about three and one-third 'times as long as broad, inner margins converging slightly towards mandibles. Mandible, malar space and galea as in female. Maxillary palpus as in female but segmental ratio about as 1.0:0.9:0.8:0.6:0.5:0.6. Labial palpus as in female but ratio about as 1.0:0.6:0.5:0.6, Labral process entire or extremely weakly emarginate apically, trapezoidal to rounded, shiny; labrum below process without cristae, shiny apically, punctate basally, convex. Clypeus, supraclypeal area, genal area, vertex and face about antennal fossae sculptured as in female.

Thoracic form and sculpturing as in female but propodeum outside of dorsal enclosure with more distinct punctures and dorsal enclosure often slightly more roughened. Wing venation as in female.

Metasomal terga 1-5 sculptured as in female terga 1-4 but punctures usually slightly smaller and less dense in apical areas. Sterna 2-5 with apical areas impunctate, discs with punctures separated by two or more puncture widths; surface dulled by fine reticular shagreening. Sternum 6 with apical margin thickened and sharply reflexed forming blunt lateral teeth. Terminalia as in Figures 94-98.

VESTITURE. Pale ochraceous except as follows: terga 2-5 with apical bands white; inner surfaces tarsi pale yellow. Form and distribution of hairs as in brevipalpis but tergal bands more distinct (interrupted medially on terga 2 and 3 and often 4).

Names
Scientific source:
Hosts · map
FamilyScientific name @ source (records)
Fabaceae  Amorpha fruticosa @ AMNH_BEE (2)

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