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Andrena principalis LaBerge, 1986
Life   Insecta   Hymenoptera   Apoidea   Andrenidae   Andrena
Subgenus: Erandrena

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Reprinted with permission of the American Entomological Society from: LaBerge, W. E. 1985. A revision of the bees of the genus Andrena of the Western Hemisphere. Part XI. Minor subgenera and subgeneric key. Transactions of the American Entomological Society 111: 440-567.

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This remarkable oligolege of manzanita (Arctostaphyllos spp.) from California is easily recognized by the subgeneric characters. Both sexes have much elongated mouthparts; shiny stipites with long, simple hairs; a greatly protuberant clypeus; and the face above the antennal fossae tessellate. The male has a partially yellow clypeus, and the female has relatively sparse, long, simple, scopal hairs. Both sexes have the humeral angles and dorsoventral ridges of the pronotum extremely poorly developed.

FEMALE. MEASUREMENTS AND RATIOS: N = 20; length, 9-11 mm width, 3.1-3.5 mm; wing length, M = 4.03 0.163 mm; FL/FW, M = 1.02 0.031; FOVL/FOVW, M = 2.76 0.080.

INTEGUMENTAL COLOR. Black except as follows: mandible with apical third rufescent; flagellum below dark brown to black; tegula piceous; wing membranes hyaline, veins dark reddish brown to black; tibial spurs testaceous; terga with extremely narrow apical margins hyaline, dark rufescent just basad of hyaline margins; sterna 2-5 with apical areas translucent, colorless at apical margins to rufescent basally.

STRUCTURE. Antenna long; scape length equals first three and one-third flagellar segments; flagellar segment 1 longer than segment 2 plus 3; segment 2 about as long as broad, as long as segment 3; segments 4-9 longer than broad. Eyes each about three and one-half times as long as broad, inner margins converging slightly toward vertex. Malar space moderately long, minimum length about one-fourth as long as basal mandibular width. Mouthparts greatly elongate, galeae and glossa longer than median clypeal length; galea narrow, outer-apical margin straight, surface shiny, unshagreened or weakly so. Stipites shiny, with moderately long, spine-like, simple hairs. Mandible moderately long, when closed extending beyond midlabrum by about one-fourth its length. Maxillary palpus long, segmental ratio about 1.0:1.0:0.8:0.6:0.5:0.4. Labial palpus long, ratio about 1.0:0.9:0.9:0.7. Labral process flat, entire or gently emarginate (holotype), broad, usually three times as broad as long; labrum apical to process as long as process or longer, convex, shiny, with weak median crista often present. Clypeus strongly protuberant; punctures sparse or absent apicomedially, irregularly dispersed basally and laterally; usually shiny in apical third to two-thirds and shagreened at base and laterally, occasionally mostly shagreened. Supraclypeal area finely reticularly shagreened. Face above antennal fossae dull, tessellate, with punctures more crowded below near fossae and sparse above near ocelli. Facial fovea broad, shallow, separated from lateral ocellus by about three-fourths an ocellar diameter, extending to line at lower margins antennal fossae or slightly below. Vertex above lateral ocellus equals about one ocellar diameter; tessellate with round punctures along apex and especially above ocelli. Genal area in profile distinctly broader than eye (almost as 3:2), shiny near eye and dull posteriorly, reticularly shagreened with minute sparse punctures.

Pronotum with extremely weak humeral angle, dorsoventral ridge only weakly expressed in its lower half (angle and ridge so poorly formed that this subgenus will be readily confused with subgenera lacking these structures); surface reticularly shagreened. Mesoscutum finely tessellate with scattered round punctures separated by two to three or more puncture widths. Scutellum similar but usually shinier, shagreened. Propodeum on all surfaces reticularly shagreened; dorsolateral and posterior surfaces with sparse obscure punctures. Mesepisternum finely shagreened, punctures obscure (almost imperceptible in holotype), sparse.

Metasomal terga 1-4 reticularly shagreened, punctures absent or virtually so. Pygidial plate V-shaped with broadly rounded apex, internal raised triangular area present. Sterna 2-5 with narrow apical areas impunctate; basal areas with crowded punctures near apical areas to sparsely punctate near bases; surfaces finely shagreened.

VESTITURE. Pale ochraceous except as follows: vertex and face above antennal fossae with dark brown hairs; facial fovea with short dark brown to pale brown or golden hairs and longer dark brown hairs scattered throughout (longer hairs half as long as facial hairs or shorter); mesoscutum and scutellum with long brown hairs medially; propodeum with dorsolateral and posterior surfaces often with dark hairs mixed with the pale; tergum 4 or terga 3 and 4 with short basal area hairs brown at least in part; terga 5 and 6 dark brown except laterally; outer surfaces tarsi and fore and middle tibiae dark brown; hind tibia with scopal hairs at least half brown, white along anterior margin or in anterior half. Propodeal corbiculum incomplete anteriorly, interior with abundant long simple hairs. Trochanteral flocculus complete, full. Tibial scopal hairs long, simple, sparse.

MALE. MEASUREMENTS AND RATIOS. N = 20; length, 9-11 mm; width, 2.0-2.5 mm; wing length, M = 3.62 0.146 mm; FL/FW, M = 1.03 0.009; FS1/FS2, M = 1.14 0.064.

INTEGUMENTAL COLOR. Black with same exceptions as female, but clypeus yellow except narrow apical margin and posterior third to one-half (yellow area often three-lobed posteriorly).

STRUCTURE. Antennae moderately long; scape length equals slightly more than first two flagellar segments; flagellar segment 1 as long as or slightly longer than segment 2; flagellar segments each distinctly longer than broad. Eyes each about three and one-third times as long as broad, inner margins parallel. Malar space, galeae, and glossa as in female. Stipites as in female but spine-like hairs longer. Mandibles decussate, long, with subapical tooth. Maxillary palpus as in female, but segmental ratio about 1.0:0.9:0.8:0.7:0.6:0.6. Labial palpus as in female but ratio about 1.0:0.9:0.7:0.7. Labral process exceedingly shallow, flat, shiny, weakly bidentate; labrum apical to process convex, shiny; labrum at least three-fourths as long as broad. Clypeus as in female, but punctures sparser and usually shiny except narrow posterior area. Supraclypeal area and face above antennal fossae as in female, but face occasionally with short, weak, parallel rugulae near fossae (not extending to ocelli). Vertex as in female. Genal area broad, in profile one and one-half times as broad as eye or broader, genal area broadest at level of upper third of eye; surface sculptured as in female.

Thoracic form and sculpturing as in female, but propodeal dorsal enclosure often weakly roughened at extreme base (not in allotype).

Metasomal terga 1-5 sculptured as in female terga 1-4 but shinier, especially in apical areas, shagreening weaker and punctures slightly more evident but extremely sparse. Tergum 7 lacks pygidial area. Sterna 2-5 with apical areas impunctate, basal areas sparsely punctate throughout, surfaces moderately shiny, weakly shagreened. Sternum 6 flat, emarginate. Terminalia as in figures 64-68. Note sternum 7 with U-shaped apical emargination and sternum 8 almost entire apically (much as in Anchandrena ).

VESTITURE. Color as in female, but black facial hairs present near inner margin eye down to lateral angle of clypeus, upper third or more of genal area with dark hairs, propodeal hairs largely dark brown to largely pale; terga 4 and 5 or 3-5 with basal area hairs brown; terga 6 and 7 brown medially; outer surfaces tarsi and tibiae with pale hairs.

Scientific source:

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FamilyScientific name @ source (records)
Ericaceae  Arctostaphylos pungens @ BBSL (1)

Arctostaphylos sp @ BBSL (1)

Arctostaphylos @ AMNH_BEE (7)
_  Withheld @ BBSL__YOSE (8); BBSL (4)

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Updated: 2024-04-21 12:23:35 gmt
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