Smithsonian Institution, Entomology Department · 9
Andrena salicifloris, male, face
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Reprinted with permission of the American Entomological Society from:
LaBerge, W. E. 1973. A revision of the bees of the genus Andrena of the Western Hemisphere. Part VI. Subgenus Trachandrena. Transactions of the American Entomological Society 99: 235-371.
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Andrena salicifloris is a common western species closely related to A. sigmundi. The female of salicifloris differs from that of sigmundi by having longer tergal hairs and the mesoscutum much more densely punctate in the anterior third or fourth. The male of salicifloris can be readily told from that of sigmundi by the longer tergal hairs (especially in the basal areas of terga 2 and 3) and the more densely punctate mesoscutum. Both sexes of salicifloris differ from other species of Trachandrena by the same characters that distinguish sigmundi.
FEMALE. MEASUREMENTS AND RATIOS. — N = 20; length, 9-12 mm; width, 3.0-3.5 mm; wing length, M = 4.21 ± 0.176 mm; FL/FW, M = 1.01 ± 0.004; FOVL/FOVW, M = 3.44 ± 0.069.
INTEGUMENTAL COLOR. — Black except as follows: mandible with apical third often rufescent; flagellar segments 3-10 dark brown below; tegula occasionally rufescent at summit, usually piceous; wing membranes hyaline, only slightly infumate if at all, veins dark reddish-brown; tibial spurs testaceous to rufescent.
STRUCTURE. — Antennal scape length equal to first three and one-half to three and three-fourths flagellar segments; flagellar segments as in sigmundi. Eyes each about three and two-thirds times as long as broad, inner margins parallel. Malar space and galea as in sigmundi. Maxillary palpus as in sigmundi but segmental ratio about as 1.0:1.0:0.9:0.8:0.8:0.8. Labial palpus as in sigmundi but ratio about as 1.0:0.5:0.5:0.5. Labrum, clypeus, supraclypeal area, genal area and vertex as in sigmundi. Face above antennal fossae with coarse contiguous punctures separated by mere ridges or with round deep punctures separated by half to one puncture width or slightly more, when punctures separated, surface shiny. Facial fovea as in sigmundi.
Pronotum as in sigmundi. Mesoscutum densely punctate especially in anterior fourth or third where punctures are large and separated by sharp ridges, posteromedially punctures well separated, surface finely tessellate, dull except in moderately shiny posteromedial area. Scutellum with dense coarse punctures separated mostly by half a puncture width or slightly less, surface dull to moderately shiny. Propodeum sculptured as in sigmundi but dorsal area rugae less regular and not as coarse. Mesepisternum and front femora as in sigmundi. Posterior hind tibial spur almost always bent in outer third as in sigmundi. Wing venation and pterostigma as in sigmundi.
Metasomal terga 1-4 sculpturing similar to that of sigmundi but in general punctures more crowded and apical areas of terga with impunctate margins narrower, usually one-fifth or less of apical area medially on each tergum impunctate. Pygidial plate, unless worn, narrowly V-shaped with distinct triangular, sharply pointed, internal raised area with small crowded punctures contrasting with smooth, shiny margins. Sterna as in sigmundi.
VESTITURE. — Generally ochraceous, often dark ochraceous to reddish on thoracic dorsum and vertex; inner hind tibiae reddish-yellow to yellow. Disposition and form of hairs as in sigmundi except as follows: hairs generally longer; interrupted tergal fasciae present on terga 2-4 (unless worn) and composed of relatively long pubescence.
MALE. MEASUREMENTS AND RATIOS. — N = 20; length, 8-11 mm; width, 2.0-2.5 mm; wing length, M = 3.82 ± 0.193 mm; FL/FW, M = 1.09 ± 0.005; FS1/FS2, M = 0.71 ± 0.014.
INTEGUMENTAL COLOR. — Black with same exceptions as female except as follows: flagellar segments 2-11 dark brown below; tegula often rufescent at summit; wing membranes hyaline.
STRUCTURE. — Antennae as in sigmundi. Eyes each three and one-half to three and two-thirds times as long as broad, inner margins converging towards mandibles. Malar space, mandible and galea as in female. Maxillary palpus as in sigmundi but segmental ratio about as 1.0:1.0:0.9:0.9:0.9:0.9. Labial palpus as in sigmundi but ratio about as 1.0:0.7:0.7:0.8. Labrum as in sigmundi. Clypeus, supraclypeal area and vertex as in female. Genal area as in female but laterally with fine rugulae posteriorly and surface moderately dulled by fine shagreening. Face above antennae punctatorugose, rarely with distinct punctures and shiny interspaces.
Pronotum normal, as in female. Mesoscutum with round shallow punctures in anterior third separated by half a puncture width or less, sparser posteromedially, surface dulled by fine tessellation. Scutellum with crowded shallow punctures, dulled by fine tessellation. Propodeum as in female but rugae coarser and lateral surfaces finely punctatorugose and dulled by fine tessellation. Mesepisternum finely punctatorugose, moderately dulled by extremely fine tessellation. Posterior hind tibial spur and wing venation as in sigmundi.
Metasomal terga sculptured much as in female. Tergum 2 with apical area slightly shorter medially than basal area. Sterna 2-5 sparsely punctate, dulled by coarse reticular or transversely reticular shagreening. Sternum 6 as in sigmundi, apical margin sinuous. Terminalia as in sigmundi; see figures 22-23.
VESTITURE. — Usually dark ochraceous to ochraceous, vertex and thoracic dorsum slightly darker. Terga 2-5 with apical bands as in sigmundi but composed of longer pubescence. Terga 2 and 3 with basal areas with long suberect plumose hairs, on tergum 2 usually about as long as apical area.
REMARKS. — Collections from California, particularly from central and southern parts of the state, have females in which the face above the antennal fossae have distinct punctures separated by half a puncture width or more and the interspaces are shiny. No difference could be found between the males from California and those from elsewhere except, perhaps, they averaged very slightly smaller in size. The California populations were at first segregated as a distinct taxonomic unit and could be considered a geographical race or subspecies bearing the name nortoni. However, the differences seem slight and the cline in the female punctation character appears to be smooth toward the north so that recognizing a subspecies would seem to create more difficulties than it would solve.
Updated: 2022-05-16 08:09:25 gmt