Reprinted with permission of the American Entomological Society from:
LaBerge, W. E. 1971b. A revision of the bees of the genus Andrena of the Western Hemisphere. Part IV. Scrapteropsis, Xiphandrena, and Rhaphandrena. Transactions of the American Entomological Society 97: 441-520.
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This small Californian bee and the five species described below belong in a group of closely related species rather distinct from the remaining Scrapteropsis and probably most closely related to A. ilicis or A. fenningeri. This group of bees seems to approach the subgenus Biareolina in the form of the female facial foveae and the metasomal terga. They can be considered as annectant between the two subgenera.
A. stipator females are similar to fenningeri females in the lack of anterior or internal plumose hairs on the corbicula. The stipator females differ in having a broader space between the facial fovea and the compound eye margin, in the densely punctate scutellum and the sparsely punctate mesoscutum. The female of stipator differs from that of ilicis in the form of the facial fovea and the punctures of the scutellum but also in the propodeum being finely punctatorugose outside of the dorsal enclosure. The male of stipator has a relatively flat sixth sternum as in ilicis but has much more densely punctate scutellum and metasomal terga. In addition, the male has a rather distinct, very narrow and pointed, vestige of the pygidial plate present on the seventh sternum.
FEMALE. MEASUREMENTS AND RATIOS. — N = 20: length, 9-10 mm; width. 2.5-3.0 mm; wing length, M = 3.07 ± 0.081 mm; FL/FW, M = 0.96 ± 0.004; FOVL/FOVW, M = 3.15 ± 0.043.
INTEGUMENTAL COLOR. — Black except as follows: mandible with apical third rufescent; flagellar segments 3-10 dark brown below; wing membranes hyaline, slightly infumate, veins dark brown; distitarsi slightly rufescent. tibial spurs red to reddish-brown.
STRUCTURE. — Antennal scape length equal to flagellar segments 1-4; flagellar segment 1 equal in length to segments 2 plus 3, segment 2 equal to 3. each shorter than 4, segments 2-4 shorter than broad. Eyes each about three and one-half times as long as broad or slightly longer, inner margins parallel. Malar space mandible and galea as in imitatrix. Maxillary palpus as in imitatrix but somewhat shorter and segmental ratio about 1.0: 1.0: 0.9: 0.6: 0.6: 0.7. Labial palpus as in imitatrix but ratio about 1.0: 0.6: 0.3: 0.4. Labral process about as long as broad at base, narrowed in apical half or more. thickened and often feebly emarginate apically; labrum apical to process without transverse sulcus, punctate. Clypeus as in imitatrix but punctures more crowded, separated mostly by less than half a puncture width, median impunctate line present. Supraclypeal area with extremely minute, crowded, shallow punctures and fine shagreening dulling surface. Genal area in profile only slightly broader than eye, with small punctures, dulled by fine shagreening except in narrow band near eye, without rugulae laterally: ventral surface with weak longitudinal rugulae and scattered punctures. if rugulae moderately well formed, then almost parallel with hypostomal carinae, not strongly converging towards mandibles. Vertex short, above lateral ocellus equals half an ocellar diameter or slightly more, surface with small punctures, shiny above compound eyes, dulled by shagreening medially. Face above antennal fossae with strong, irregularly longitudinal rugae and abundant large interrugal punctures. Facial fovea shallow, extending down to below level of lower margins antennal fossae, separated from compound eye by a broad, shiny, sparsely punctate area which at broadest is distinctly broader than half width of fovea at that level, separated from lateral ocellus by one ocellar diameter or slightly less.
Pronotum normal, without humeral angles or these extremely weakly formed and without distinct dorsoventral ridge; sculptured as in imitatrix. Mesoscutum between parapsidal lines and from anterior to posterior declivities flat. with irregularly-sized, small, round, shallow punctures separated mostly by one to five puncture widths or more., posterior margin with band of crowded punctures four or five rows wide; surface opaque, tessellate. Scutellum and metanotum flat, with crowded punctures separated by mere ridges. Propodeum with dorsal enclosure with several longitudinal rugae becoming irregular apically. interrugal surface shiny; dorsolateral and posterior surfaces extremely finely punctatorugose and tessellate; lateral surface extremely weakly rugulate in posterior half, with small scattered punctures, moderately shiny. Mesepisternum coarsely punctatorugose, punctures smaller and separated in posterior sixth or less, bottoms of punctures shiny. Hind femur without ventral ridges; hind tibia moderately broad, broadest near apex: middle femur broad, 2.1 to 2.6 times as long as broad. Wing venation as in imitatrix but pterostigma somewhat narrower.
Metasomal tergum 1 with basal area punctures irregular in size, separated mostly by two to four puncture widths, smaller and more crowded in narrow median area; apical area punctures small, crowded, separated by less than half a puncture width; surface shiny. Tergum 2 similar to 1 but with punctures becoming small and crowded at extreme base as well as medially in basal area. Terga 3 and 4 similar to 2 but apical area punctures progressively smaller although always distinct. Pygidial plate V-shaped with rounded apex, small raised internal triangular area present. Sterna 2-5 with narrow apical areas and crowded punctures basally, surfaces shagreened.
VESTITURE. — Generally white but vertex may have yellowish-brown long hairs, on and surrounding hind basitibial plates brown, outer surfaces fore and middle tibiae with some brown, terga 5 and 6 with some brown.
MALE. MEASUREMENTS AND RATIOS. — N = 11; length. 7-9 mm; width. about 2 mm; wing length, M = 3.01 ± 0.179 mm; FL/FW, M = 1.05 ± 0.010; FS1/FS2, M = 0.99 ± 0.006.
INTEGUMENTAL COLOR. — Black except as follows: mandible with apical third rufescent; flagellar segments 2-11 dark brown below; wing membranes hyaline, colorless, veins dark reddish-brown; tergal apical areas hyaline to translucent, clear apically to yellow or yellowish-brown basally; distitarsi rufescent; tibial spurs testaceous.
STRUCTURE. — Antennae rather short in repose, not surpassing scutellum; scape length equal to first two and one-fourth flagellar segments; flagellar segments all longer than broad. Eyes as in imitatrix. Mandible, galea. malar space as in female. Maxillary palpus as in female but segmental ratio about 1.0: 1.0: 0.8: 0.8: 0.6: 0.5. Labial palpus as in imitatrix but ratio about 1.0: 0.7: 0.5: 0.5. Labral process large, thickened in apical half or more. usually deeply emarginate apically; apical part of labrum without sulcus, punctate, shiny. Clypeus as in female but punctures smaller, more crowded, impunctate midline narrower. Supraclypeal area and vertex as in female. Genal area in profile about as broad as eye (allotype) or slightly broader, laterally with rather coarse punctures and reticular shagreening but no rugulae, ventrally with weak. irregular, longitudinal rugulae. punctures and weak shagreening. Face above antennal fossae moderately coarsely to coarsely punctatorugose. bottoms or large punctures moderately shiny.
Pronotum as in female. Mesoscutum much as in female but punctures slightly larger and shallower and much more crowded, between parapsidal lines separated mostly by half to one puncture width and elsewhere more crowded. Scutellum and metanotum as in female. Propodeum as in female but dorsal enclosure with rugulae more irregular and lateral surfaces similar to posterior surface. Mesepisternum as in female. Wing venation as in female; one specimen (not allotype) with two submarginal cells in one wing. Legs as in imitatrix but hind tibia not swollen medially, broadest at apex.
Metasomal tergum 1 as in female but apical area punctures slightly less crowded. Terga 2-5 as in female terga 2-4 but basal area punctures regularly spaced and separated mostly by half to one puncture width and narrow apical areas slightly less punctate than in female. Tergum 7 with narrow. sharply pointed, small but distinct, vestige of pygidial plate. Sterna 2-5 with narrow apical areas; basal areas sparsely punctate, moderately shiny, with reticular shagreening. Sternum 6 flat or almost so. emarginate apically.
Terminalia as in figures 44-48; note the following: sternum 7 shallowly emarginate, with only a few minute hairs; gonocoxite with dorsal lobe strongly curved ventrally (toward penis valve); penis valve with strong lateral dorsal lamella.
VESTITURE. — Generally white; form and distribution as in female but lacking pollen-collecting hairs; terga without apical pale fasciae.