Smithsonian Institution, Entomology Department · 9
Andrena xanthigera, female, face |
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Smithsonian Institution, Entomology Department · 9
Andrena xanthigera, female, side |
Smithsonian Institution, Entomology Department · 9
Andrena xanthigera, female, top |
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Smithsonian Institution, Entomology Department · 9
Andrena xanthigera, female, wing |
Smithsonian Institution, Entomology Department · 1
Andrena xanthigera, top |
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Overview |
Reprinted by permission of the Regents of the University of California from:
Donovan, B. J. 1977. A revision of North American bees of the subgenus Cnemidandrena (Hymenoptera: Andrenidae). University of California Publications in Entomology: 1-107.
Please report text errors to: leah at discoverlife dot org.
A. xanthigera can be distinguished from other species within the Nubecula group by the presence of an apical fascia on metasomal tergum 1 with the wing darkened apically and in the marginal cell. The males have the posterior margin of the gena prominently spine-like opposite the mid-point of the compound eye (fig. 6).
FEMALE. MEASUREMENTS AND RATIOS. — -N = 13; length, 6.3-7.9 mm; width, 1.9-2.5 mm; wing length, M = 2.37 ± 0.148 mm; FL/FW, M = 1.02 ± 0.070; FOVL/FOVW, M = 3.77 ± 0.207.
INTEGUMENTAL COLOR. — Black except as follows: antenna yellow-brown ventrally beyond second flagellar segment; mandible with apical half red; tibial spurs white; mediotarsi, distitarsi, basal half of tarsal claws light brown-yellow; apical half of tarsal claws red; tegula hyaline light brown; wing veins dark brown, pterostigma nearly black; wing membrane apically and in area of marginal cell moderately to strongly darkened; remainder hyaline to very lightly darkened; metasomal terga and sterna moderately widely hyaline apically; pygidial plate black apically and laterally, median area dark red.
STRUCTURE. — Scape equal to flagellar segments 1 to 3 plus half of flagellar segment 4; flagellar segment 1 equal to flagellar segments 2 plus 3; flagellar segment 2 shorter than flagellar segment 3. Eye 3.5 times longer than wide, with inner margin diverging above except for upper end incurved. Malar space 8 times wider than long. Mandible in repose with less than one-third its length projecting beyond middle of labrum, with notch of mandible tooth equidistant between middle of labrum and mandible apex. Galea moderately tessellate, with dorsal surface somewhat wider than lateral surface. Maxillary palpus with half of apical segment projecting beyond apex of galea; segmental ratio 0.8:0.8:0.6 :0.7:0.6:0.7. Labial palpus with basal segment laterally compressed and curved, apical segment attached somewhat subapically, segmental ratio 0.9:0.6:0.5:0.6. Labral process nearly flat, trapezoid, twice as wide as long, apical emargination shallow, depth one-fifth length of labral process. Clypeus moderately protuberant, extending below eyes for less than one-half its length, with large punctures, separated widely in lower, median area leaving a small impunctate area; punctures smaller, closer near upper and outer periphery, upper third moderately shagreened, remainder shiny. Supraclypeal area with irregular punctures obscured by moderate shagreening. Genal area less than twice width of eye, with small punctures separated by 1 diameter, third nearest eye shiny, remainder moderately shagreened. Vertex above lateral ocellus equal to slightly more than 1 ocellar diameter, with weak tessellation obscuring medium-sized punctures, punctures separated by 1 diameter. Supra-antennal area with longitudinal rugulae with obscure, interrugal punctures. Facial fovea deeply impressed, 4 times longer than wide, of almost equal width throughout except slightly wider above, rounded above and below, reaching above to a line slightly above median ocellus, reaching below to a line below antennal fossa.
Pronotum with humeral angle and ridge well developed, weak pronotal suture crossing humeral ridge, humeral ridge broadly and shallowly depressed medially, pronotum with obscure, medium-sized punctures dorsally, with moderate shagreening throughout. Scutum with medium-sized punctures separated by 4 diameters, anterior area moderately shagreened, shagreening decreasing dorsally, dorsal area very lightly shagreened, nearly shiny. Scutellum, metanotum as for dorsal area of scutum except shagreening light. Propodeal enclosure with anterior third with irregular, longitudinal rugulae, remainder weakly tessellate with shallow, median, longitudinal depression; dorsoposterior area with medium-sized punctures separated by 3 to 4 diameters, moderately tessellate, lateral, corbicular area with small to medium-sized punctures separated by 2 to 4 diameters in anterodorsal third or less, with light, reticular shagreening, surface shiny. Mesepisternum with medium-sized punctures separated by 3 diameters, moderately shagreened. Metepisternum very lightly shagreened, shiny. Mesobasitarsus widest medially, 3 times longer than wide, wider than metabasitarsus. Metabasitarsus widest near base, narrowing apically, a little more than 4 times longer than wide, two-thirds width of metatibia. Metatibia cuneate, curved ventrally, widest apically, 3.5 times longer than wide. Tibial spurs normal. Wing with pterostigma 4 times longer than wide, vein 1st m-cu meets second submarginal cell at or slightly beyond middle.
Metasomal terga 1 to 4 with small punctures on apical margins of discs separated by 2 diameters; tergum 1 with small punctures laterally and anteriorly on disc; tergum 4 with sparse, widely scattered punctures on disc separated by 2 diameters; terga 1 to 5 with weak tessellation. Pygidial plate narrowly rounded apically, with lateral edges raised, middle flat, with small, close punctures throughout. Sternum 1 with shallow, median emargination, sterna 1 to 6 with punctures separated by 2 diameters except sterna 3 to 6 with broad, median, anterior, impunctate areas; punctures on sternum 1 medium-sized; punctures on sterna 2 to 6 small; punctures 1 to 6 with very light, reticular shagreening, shiny.
VESTITURE. — White throughout. Clypeus with hairs very sparse, nearly naked medially. Scutum, scutellum with very sparse vestiture. Propodeal corbicula with sparse, erect, plumose hairs in anterodorsal third or slightly less. Trochanteral floccus imperfect.
Metasomal terga 1 to 4 with narrow, apical fasciae of short, appressed hairs, fascia of tergum 1 with hairs moderately dense, not obscuring surface, hairs not all appressed, fasciae of terga 2 to 4 obscuring one-third of terga or less, tergum 1 with disc with hairs laterally and anteriorly, tergum 2 with disc naked, terga 3 and 4 with very short, sparse, very fine, erect hairs on discs. Sternum 1 with apical fringe moderately well developed, sterna 2 to 5 with apical fringes weakly present laterally, absent medially; hairs of apical fringes becoming longer, more erect posteriorly; sternum 1 with long, erect hairs, sterna 2 to 5 with subapical fimbriae moderately developed laterally, poorly developed medially; remainder of sternal area with erect hairs except sterna 3 to 6 with impunctate anterior, median areas naked.
MALE. MEASUREMENTS AND RATIOS. — N = 16; length, 4.9-6.2 mm; width, 1.4-1.7 mm; wing length, M = 1.94 ± 0.102 mm; FL/FW, M = 0.96 ± 0.081; FS1/FS2, M = 1.20 ± 0.022.
INTEGUMENTAL COLOR. — Black except as follows: antenna red-brown ventrally beyond first flagellar segment; mandible with apical third red; tarsi red-brown, tarsal claw with basal half yellow, apical half red; tegula, wing as in female; metasomal terga with apical, depressed area hyaline, sterna widely hyaline apically.
STRUCTURE. — Scape equal to flagellar segments 1 and 2 plus half of flagellar segment 3; flagellar segment 1 a little longer than flagellar segment 2; flagellar segment 2 equal to flagellar segment 3. Eye 3 times longer than wide with inner margin moderately diverging above except for upper end incurved. Malar space, mandible and galea as in female. Maxillary palpus with half of apical segment or more projecting beyond apex of galea, segmental ratio 0.6:0.5:0.5:0.5:0.4:0.5. Labial palpus as in female except segmental ratio 0.7:0.4:0.4:0.3. Labral process very strongly reflexed, width twice length, apical emargination depth one-third length of reflexed area. Clypeus weakly protuberant; extending below eyes for less than one-third its length; with large punctures throughout separated by less than 1 diameter except more widely spaced in lower median area; shiny. Supraclypeal area as in female. Genal area 1.5 times wider than eye; genal area produced to a prominent spine opposite midpoint of eye; posterior margin above eye weakly carinate (fig. 6); sculpturing as in female. Vertex as in female. Supraclypeal area with frontal line strongly developed, longitudinal rugulae weakly developed medially, more strongly developed laterally, punctures obscure. Parocular areas with medium-sized, close punctures.
Pronotum with humeral angle and ridge strongly developed, humeral ridge almost carinate, broadly and shallowly depressed medially; pronotal suture obscure; sculptured as in female except nearly shiny beneath humeral ridge. Remainder of thorax as in female except scutum, scutellum smooth, shiny dorsally.
Metasomal terga 1 to 5 with small punctures on discs, separated on apical margins of discs by 2 diameters; terga 1 and 2 with discs almost impunctate; terga 3 to 5 with punctures separated by 3 diameters, with very light shagreening, shiny. Sterna 1 to 6 as in female except impunctate areas of sterna 3 to 6 small. Sternum 7 (fig. 63) with basal apodemes narrowing and smoothly rounded basally; apex truncate, lateral shoulder areas with sparse hairs. Sternum 8 (fig. 64) with apex and neck region nearly twice length of basal region; apex expanded, neck with abundant, long hairs. Gonoforceps (figs. 60 to 62) in dorsal and ventral view rounded apically, with oblique ridge not reaching outer edge. Penis valves in dorsal and ventral view widest medially with sides smoothly rounded, apex narrowly lobe-like; in lateral view down-curved, projecting well below and longer than gonoforceps.
VESTITURE. — Silvery white throughout. Clypeus obscured by long, dense hairs. Scutum, scutellum nearly naked, with very sparse, long, erect hairs. Metafemur with hairs very silvery white on anterior and dorsal surface.
Metasomal terga 1 to 4 with poorly formed, apical fasciae of sparse, semi-appressed hairs, fasciae present on less than one-third of tergal area, not obscuring surface; tergum 1 with hairs of fascia longer, more erect; remainder of disc of terga with short hairs laterally, disc with very fine, short, erect, sparse hairs dorsally except tergum 1 nearly naked. Sterna 2 to 5 with apical fringes very well developed, sterna 1 to 6 with remaining area with erect hairs, hairs shortest anteriorly.
VARIATION. — Four females from 24 km S.W. Concho, Apache Co., Arizona, are larger than average, and vein 1st m-cu meets second submarginal cell about one-third of the distance from the end of the cell. One female from Emery Co., Utah, has only two submarginal cells in the right wing, and the second submarginal cell in the left wing is only half normal width.
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Updated: 2024-04-25 12:11:43 gmt
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