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Notes from Mike Arduser: Many unusual things about this species, the dense hind tibial scopae being one. The scutum has virtually no hairs except under high mag (60x plus) you can see miniscule hairs; the propodeal scopa has absolutely zero hairs anteriorally; facial foveae very long and very narrow; mid-basitarsi just slightly wider than hind basitarsi. T1-T5 are completely finely punctate to the very rim, and the humeral angle of the pronotum is present though weak, but the dorso-ventral ridge is basically absent, represented only "by a shadow" if that.
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 small eastern species can be distinguished from its nearest relative, A. mackieae, by the characters mentioned in the diagnosis of that species. In addition, the dorsum of the thorax of the female of cerebrata has extremely short fragile hairs and appears almost nude.
FEMALE. MEASUREMENTS AND RATIOS: N = 5; length, about 10 mm; width, 2.5-3.0 mm; wing length, M = 3.32 � 0.284 mm; FL/FW, M = 1.13 � 0.008, FOVL/FOVW, M = 6.07 � 0.345.
INTEGUMENTAL COLOR. � Black except as follows: mandible with apical half or more dark rufescent; face along clypeofrontal suture often rufescent; flagellar segments 3 or 4-10 dark brown to dark reddish brown below; wing membrane hyaline, yellow, veins red to reddish brown; tegulae brown, translucent at summit; terga 1-4 with apical areas translucent; sterna 2-5 apically hyaline, basally rufescent; distitarsi dark brown to red; tibial spurs yellow.
STRUCTURE. � Antennal scape as long as first four flagellar segments or slightly less; flagellar segment 1 equals slightly more than segment 2 plus 3, which are each broader than long; median segments slightly longer than broad. Eyes each three times as long as broad or slightly less, inner margins converging slightly toward vertex. Malar space short, linear. Mandible bidentate, overlapping by one-third mandible length, without tooth or angle on basal inferior margin. Galea broad, outer margin concave in apical half; surface dull, finely and reticularly shagreened. Maxillary palpus normal in length; segmental ratio about 0.9:1.0:0.9:0.6:0.6:0.8. Labial palpus with long, flattened first segment; ratio about 1.0:0.4:0.4:0.5. Labral process trapezoidal, entire or extremely weakly emarginate, shiny with transverse sulcus at base; labrum below process convex, shiny medially, without cristae. Clypeus not much flattened, with round punctures irregularly separated by half to one or two puncture widths, surface moderately dulled by reticular shagreening. Supraclypeal area dulled by minute crowded punctures and shagreening. Face above antennal fossae dulled by longitudinal rugae and interrugal punctures. Facial fovea extremely long, narrow, extending to below a line at posterior margin clypeus, separated above from lateral ocellus by one ocellar diameter or more. Vertex above lateral ocellus equal to distinctly less than one ocellar diameter, strongly ridged and slightly peaked above median ocellus; surface punctate, tessellate, opaque. Genal area in profile about as broad as eye, surface dull, shagreened.
Pronotum with weak humeral angle and lacks dorsoventral ridge (much as in females of Conandrena); oblique suture distinct; surface shagreened. Mesoscutum with small round punctures separated mostly by half to one puncture width (somewhat sparser posteromedially); surface dull, reticularly shagreened. Scutellum similar. Metascutum similar but duller, punctures more crowded. Propodeum with dorsal enclosure entirely or almost entirely roughened by irregular anastomizing rugulae; outside of enclosure surface opaque, tessellate, and minutely punctured. Pleurae dull, shagreened. Fore wing with second submarginal cell short, receiving vein 1st m-cu near outer third of cell; pterostigma broad.
Metasomal tergum 1 with minute punctures separated mostly by one to two puncture widths; surface moderately full, reticularly shagreened. Terga 2-4 similar, but apical areas show more punctures than in tergum 1. Pygidial plate V-shaped with blunt or rounded apex and distinct raised internal triangle. Sterna 2-5 with basal area minutely punctate and reticularly shagreened; narrow apical area shagreened, impunctate.
VESTITURE. � Pale ochraceous to white except terga 5 and 6 brown medially and basitibial plates dark brown. Dorsum of thorax with hairs minute, scarcely visible, not at all hiding surface. Trochanteral flocculus complete; tibial scopal hairs, although short, highly plumose throughout. Terga 2-4 with narrow, broadly interrupted, white, apical fasciae.
MALE. MEASUREMENTS AND RATIOS. � N = 7; length 8-9 mm; width, 1.5-2.0 mm; wing length, M = 2.76 � 0.192 mm; FL/FW, M = 1.08 � 0.004; FS1/FS2, M = 1.64 � 0.061.
INTEGUMENTAL COLOR. � As in female except as follows: clypeus yellow except apical margin, small tentorial maculae, and extreme lateral lobes.
STRUCTURE. � Antennal scape as long as following two and one-half flagellar segments; flagellar segment 1 shorter than segment 2 plus 3; segment 2 about as long as broad; segments 3-11 longer than broad. Mandibles long, decussate, tips approaching lower genal protuberances when closed. Eyes each about three and one-third times as long as broad; inner margins converging slightly toward vertex. Malar space, galeae, maxillary palpus, and labial palpus as in female. Labral process small, rounded apically, shiny, hidden under protruding margin of clypeus. Clypeus protrudes apicomedially, relatively flat, with minute sparse punctures, surface shiny, shagreening weak or absent. Supraclypeal area, face above antennal fossae, and vertex as in female. Genal area broad, in profile broader than eye, below and lateral of lower end of eye with a blunt protrusion, which may measure half length of eye but usually shorter; surface dulled by reticular shagreening and minute punctures.
Pronotum with well-formed humeral angle and strong dorsoventral ridge, which is broadly interrupted just below humeral angle; oblique pronotal suture not visible; surface moderately shiny posterior to ridge, reticularly shagreened. Thoracic sculpturing as in female, but mesoscutal-scutellar punctures sparse, separated by two to four puncture widths or more; wing venation as in female.
Metasomal tergum 1 impunctate or punctures minute, sparse; surface shiny, extremely weakly shagreened. Terga 2-5 with small round punctures separated by two to four or more puncture widths, surfaces shiny to moderately shiny, shagreening absent or weak, progressively denser towards posterior. Tergum 6 without pygidial area. Terga 2-5 with small to minute punctures separated by three or more puncture widths; surfaces shiny to moderately so, reticular shagreening weak. Sternum 6 flat, emarginate. Terminalia as in figures 104-108. Note narrow, acute penis valves and apicolateral gonocoxite lobes, short dorsal lobe of gonocoxite, deeply emarginate sternum 7 and sternum 8 apically entire with narrowest width near base of neck.
VESTITURE. � Generally white to pale ochraceous, no dark hairs present. Vestiture relatively short and sparse; terga 2-5 with extremely weak, narrow, lateral remnants of apical pale fasciae. Sterna 3-5 with strong subapical fimbriae of long ochraceous, slightly curved hairs. Sternum 2 with small median remnant of subapical fimbria.
Reprinted with permission from: Mitchell, T.B. 1960. Bees of the Eastern United States. North Carolina Agricultural Experiment Station Technical Bulletin No. 141.
MALE � Length 8 mm.; face slightly longer than distance between eyes; eyes slightly divergent below; lateral ocelli separated from margin of vertex by nearly twice their diameter; cheeks much broader than eyes, with an extremely large, ventral lobe projecting at right angles to lower end of eye; clypeus broad and quite flat, but projecting about one-half below suborbital line, entirely yellow except for the very narrow marginal strip and a pair of dark spots, shining, with minute and rather sparse, vague punctures; face below ocelli dull, finely substriate; vertex somewhat shining, with a few minute, vague punctures medially, these becoming more distinct and the surface more shining just above each eye; cheeks somewhat shining and smooth, with minute, evenly spaced punctures; process of labrum rather broadly triangular but quite small, completely hidden by the markedly overlapping clypeal margin; mandibles elongate and slender, tip of one reaching base of other when closed, with an exceedingly minute, subapical, inner tooth near tip; basal segment of flagellum somewhat longer than 2nd but much shorter than 2nd and 3rd combined, median segments considerably longer than broad; pubescence of head and thorax erect, rather copious, of moderate length, entirely pale ochraceous, somewhat deeper ochraceous in dorsum of thorax: scutum and scutellum somewhat shining, punctures very fine, rather evenly distributed, well separated but hardly sparse; pleura smooth but rather dull, with fine, rather obscure, shallow punctures which are spaced about as those on dorsum; dorsal area of propodeum poorly defined, very finely subreticulate toward base, becoming more tessellate toward lateral margins, lateral areas finely tessellate, propodeal corbicula rather well developed; legs dark, slender, entirely pale pubescent, spurs pale yellowish; wings subhyaline, veins and stigma testaceous, 2nd submarginal hardly half length of 3rd, receiving 1st recurrent near apex; tegulae largely piceous but becoming somewhat yellowish-hyaline toward posterior margin; abdominal terga smooth and shining, with minute, evenly spaced but quite distinct punctures, apical margins rather narrowly impressed, these areas more finely punctate, with rims becoming somewhat yellowish, discal pubescence evident toward sides, entirely pale, suberect, fasciae very poorly developed, evident only toward sides of segments 2-4; sternum 7 strongly produced apically near center, this area deeply, triangularly emarginate, resulting in a pair of slender elongate lobes which have a few apical hairs; basal portion of sternum 8 more or less rounded, apical produced area rather slender at base, gradually broadening toward the abruptly truncate tip, covered with very short pale pubescence; penis valves slender and elongate, fully attaining tips of gonocoxites which are more compressed toward tips, being gradually somewhat expanded, gonocoxal lobes somewhat produced, narrowly rounded apically.
TYPE - Holotype: Male, Waynesville, N. C., April 30, 1952, 3000-4000 ft., (W. A. Stephen, on Malus) [author's coll.].
Without the female, this remarkable species cannot be assigned to any of the presently recognized subgenera.
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