Reprinted with permission of the American Entomological Society from:
Bouseman, J. K., LaBerge, W. E. 1978. A revision of the bees of the genus Andrena of the Western Hemisphere. Part IX. Subgenus Melandrena. Transactions of the American Entomological Society 104: 275-390.
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This small species from Texas (Fig. 6) is like Andrena transnigra in the color of the vestiture but can be separated from transnigra and other Melandrena species by the more densely punctate metasomal terga of both sexes and the short male antennae. In addition the female of brevicornis lacks the sulcus below the labral process and the dorsal thoracic hair of both sexes is relatively short.
FEMALE. MEASUREMENTS AND RATIOS. — N = 9; length, 9-12 mm; width, 3.5-4,0 mm; wing length, M = 4.23 ± 0.251 mm; FL/FW, M = 0.91 ± 0.007; FOVL/FOVW, M = 1.83 ± 0.046.
INTEGUMENTAL COLOR. — Black except as follows: mandible with rufescent reflections to base; flagellar segments 2-10 dark brown below; wing membranes deeply infumate, brown, veins dark brown, pterostigma reddish-brown; tergal apical areas usually with rufescent reflections; sterna with rufescent reflections; distitarsi dark rufescent.
STRUCTURE. — Antennal scape as long as first three and three-fourths flagellar segments or longer; flagellar segment 1 slightly longer than segments 2 plus 3; segment 2 about as long as segment 3, broader than long; segments 4-9 about as long as broad. Eyes each three and one-half times as long as broad or slightly shorter, inner margins parallel. Mandible, galea and stipes as in carlini. Maxillary palpus as in car/mi but segmental ratio about as 0.9:1.0:0.9:0.9:0.7:0.7. Labial palpus as in carlini but ratio about as 1.0:0.6:0.5:0.6. Labral process shiny, entire, trapezoidal with rounded apicolateral angles; labrum below process crossed by numerous short cristae, not sulcate. Clypeus moderately shiny, with abundant round punctures separated largely by half a puncture width, with narrow median impunctate line; surface lightly shagreened or unshagreened. Supraclypeal area, face above antennal fossae and facial fovea as in carlini. Vertex above lateral ocellus equals about two ocellar diameters, sculptured as in carlini. Genal area in profile almost twice as broad as eye, sculptured as in transnigra.
Pronotum, mesoscutum, scutellum and metanotum as in carlini but mesoscutum and scutellum with fine shagreening, moderately shiny. Propodeum as in carlini but dorsal area often smooth without basal roughening (holotype) and lateral surface without posterior vermiculate rugulae. Wing venation as in carlini but pterostigma narrow, not as broad as from inner margin prestigma to anterior wing margin.
Metasomal terga 1-5 with apical areas equal to about one-third median length (slightly longer on tergum 1); apical areas with narrow apical rims impunctate, otherwise with small round punctures separated mostly by one puncture width or less; basal areas similarly punctate but tergum 1 with basal area punctures separated mostly by more than one puncture width and terga 2-4 with punctures separated mostly by less than one puncture width. Pygidial plate broad basally, V-shaped with acute apex, without raised internal area. Sterna 2-5 as in carlini.
VESTITURE. — Black with dorsal thoracic hairs pale ochraceous except strong black band between tegulae; dorsal femoral hairs pale in part; usually vertex with a few brownish or ochraceous hairs; terga without fasciae. Pollen-collecting hairs normal for subgenus; dorsal thoracic hairs short.
MALE. MEASUREMENTS AND RATIOS. — N = 8; length, 9-12 mm; width, 3.0-3.5 mm; wing length, M = 4.23 ± 0.251 mm; FL/FW, M = 0.91 ± 0.007; FS1/FS2, M = 1.83 ± 0.046.
INTEGUMENTAL COLOR. — Black except as follows: mandible with rufescent reflections to base; flagellar segments 2-11 dark brown to reddish-brown below; wing membranes moderately infumate, brownish-yellow, veins reddish-brown; terga with apical areas slightly translucent, basal areas with rufescent reflections; sterna 2-5 with narrow apical rims hyaline, basally with rufescent reflections; legs dark, with rufescent reflections; tibial spurs dark reddish-brown.
STRUCTURE. — Antennae short, female-like; in repose not surpassing tegulae; scape length equals first two and one-half flagellar segments; flagellar segment 1 as long as following one and one-half segments; segment 2 shorter than segment 3 and about as broad as long; segments 3-10 only slightly longer than broad. Eyes each three and one-fourth times as long as broad, inner margins parallel to diverging slightly towards vertex. Mandible as in female, not markedly decussate. Galea and stipes as in carlini. Maxillary palpus as in carlini but segmental ratio about as 0.9:1.0:0.8:0.8:0.7:0.7. Labial palpus as in carlini but ratio about as 1.0:0.5:0.5:0.5. Labral process large, shiny, slightly bowed outwards, gently emarginate, trapezoidal; surface below process punctate, not sulcate nor cristate. Clypeus short hut distinctly longer than one-third minimum interocular distance; densely punctate and surface dulled by fine shagreening. supraclypeal area as in female. Face above antennal fossae as in female but duller, rugae less distinct. Vertex above lateral ocellus equals two ocellar diameters or almost so, dulled by small obscure punctures and dense tessellation. Genal area in profile equal to about one and one-half to one and three-fourths times eye width, surface dulled by fine shagreening and minute punctures.
Thoracic form and sculpturing as in female. Wing venation as in female (pterostigma narrow).
Metasomal terga sculptured as in female but apical area punctures smaller, icm distinct and sparser. Pygidial area not evident or extremely narrow with poorly defined margins. Sterna 2-5 sculptured as in carlini but duller, shagreening coarse. Sternum 6 with apical margin evenly convex or straight across, not produced. without raised triangular area.
Terminalia as in figures 54-58; note sternum 8 not strongly delimited at base of neck as in carlini and neck more strongly constricted than in previous species.
VESTITURE. — Generally white to pale ochraceous except as follows: terga 2-5 or 3-5 with basal areas with short erect brown hairs mixed with the pale; inner surfaces hind basitarsi yellow to red. Hairs in general relatively short; terga without fasciae.
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