Reprinted with permission of the American Entomological Society from:
LaBerge, W. E. 1977. A revision of the bees of the genus Andrena of the Western Hemisphere. Part VIII. Subgenera Thysandrena, Dasyandrena, Psammandrena, Rhacandrena, Euandrena, Oxyandrena. Transactions of the American Entomological Society 103: 1-144.
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This small bee from the southwest resembles both A. brevipalpis and A. robertsonii. Like brevipalpis the metasomal terga are shiny and punctate but tergum 2 has the punctures more crowded than in the latter. The color of the antennae and the shape of the male as in robertsonii. The vertex above the lateral ocellus is shorter than one ocellar diameter much as in robertsonii. In addition the female of coruscata has the apical pale band of tergum 3 complete or only narrowly interrupted medially.
FEMALE. MEASUREMENTS AND RATIOS. — N = 9; length, 9-10 mm; width, 2.0-2.5 mm; wing length, M = 3.40 ± 0.238 mm; FL/FW, M = l.04 ± 0.006; FOVL/FOVW, M = 4.34 ± 0.097.
INTEGUMENTAL COLOR. — As in brevipalpis but flagellum below dark reddish-brown to brown.
STRUCTURE. — Antennae, eyes, malar space and mandible as in brevipalpis. Maxillary palpus as in brevipalpis but segmental ratio about as 0.9:1.0:0.7:0.6:0.6:0.6. Labial palpus as in brevipalpis but ratio about as 1.0:0.6:0.4:0.4. Labrum, clypeus, supraclypeal area and genal area as in brevipalpis. Vertex short, above lateral ocellus equal to about three-fourths an ocellar diameter of slightly more; structure as in brevipalpis. Face above antennal fossae and facial fovea as in brevipalpis.
Thoracic form and sculpturing and wing venation as in brevipalpis, Metasomal terga 1-5 shiny, punctate as in brevipalpis but punctures more crowded, on disc of tergum 2 separated mostly by less than one puncture width. Pygidial plate and sterna as in brevipalpis.
VESTITURE. — As in brevipalpis except metasomal tergum 3 with apical pale band complete or almost so.
MALE. MEASUREMENTS AND RATIOS. — N = 12; length, 7-9 mm; width, 1.5-2.0 mm; wing length, M = 3.23 ± 0.161 mm; FL/FW, M = 1.12 ± 0.005; FS1/FS2, M = 1.08 ± 0.023.
INTEGUMENTAL COLOR. — As in brevipalpis but flagellum below dark red to dark reddish-brown.
STRUCTURE. — Antennal structure as in robertsonii. Eyes, malar space, mandible and galea as in brevipalpis. Maxillary palpus as in brevipalpis but segmental ratio about as 0.9:1.0:0.9:0.7:0.6:0.6. Labial palpus as in brevipalpis but ratio about as 1.0:0.4:0.4:0.6. Labrum, clypeus, supraclypeal area and genal area as in brevipalpis. Vertex as in robertsonii. Face above antennal fossae as in brevipalpis.
Thoracic form and sculpturing and wing venation as in brevipalpis. Metasomal terga shiny, sculptured as in brevipalpis but disc of tergum 2 with punctures separated mostly by one puncture width or less. Sterna and terminalia as in brevipalpis.
VESTITURE. — Generally as in brevipalpis but terga 2-5 with more distinct apical white bands interrupted medially on terga 2 and 3 and often 4.
REMARKS. — Two females from Minnehaha, Hennepin Co., Minnesota, seemingly are specimens of coruscata, although the head of one female is missing. These two specimens suggest strongly that this small series of specimens represents a series of hybrids between robertsonii and brevipalpis, rather than an independent species. However, two facts seem to favor the independent species hypothesis. First, the Minnesota females, although as punctate as coruscata females from Texas or New Mexico, have the apical pale band of terga 3 and 4 broadly interrupted medially (by more than half the width of each tergum) and, thus, probably represent more coarsely punctate individuals of brevipalpis. Second, the characters defining brevipalpis seem to be taken one from robertsonii and another from brevipalpis and reassembled, but are not necessarily each intermediate in state as one would expect of hybrids.
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