Reprinted with permission from the University of Nebraska State Museum from:
Ribble, D. W. 1968. Revisions of two subgenera of Andrena, Micrandrena Ashmead and Derandrena new subgenus (Hymenoptera: Apoidea). Bulletin of the University of Nebraska State Museum 8: 1-124.
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This species is known only from males which are most similar to the males of californiensis as indicated by the identical terminalia of the two species. However, there are several important differences between the two species. In penutiani the clypeus is nearly entirely yellow, long and protrudes little medially. In californiensis the clypeus is only yellow apically, shorter and more protruding. The mandible of penutiani is typical for Andrena, while in californiensis the mandible is modified; it is longer, more pointed, sharply bent in the middle and has a basal lobe on the inner margin. Andrena californiensis has a more elevated vertex that extends further posteriorly and the second flagellar segment is as long as the first but shorter than the third segment. In penutiani the second flagellar segment is much shorter than the first and the first is equal to the third.
There is a possibility that the males of penutiani are the same species as murietae, known only from females. The reasons for not considering them the same are discussed under murietae. It is even more unlikely that penutiani is a form of californiensis as there are several important specific differences. Additional evidence lending support to this line of reasoning is that the closest the males of the two species have been collected is 97 miles, while a female of californiensis has been collected within 32 miles of penutiani. This female does not exhibit an elongated clypeus (nor do any other females) that one would expect to find in the female of penutiani. In arctostaphylae both sexes have an elongated clypeus. It seems unlikely that only the males of californiensis would vary geographically in the mentioned characters, and do so significantly in less than one hundred miles.
MALE. MEASUREMENTS AND RATIOS. — Length, 4.9 mm; width of mesothorax, 1.3 mm; wing length from tegula, 4.3 mm; facial length/width, 0.89; flagellar segment 1/segment 2, 1.58.
INTEGUMENTAL COLOR. — Color as in vandykei except: nearly entire clypeus yellow, with two lateral hyaline spots; abdomen blackish apically.
STRUCTURE. — Head as in vandykei except: mandible shorter, not bent in middle, evenly curved, mandible and subapical mandibular tooth less sharply pointed than in vandykei, posterior margin without lobe at base; galea with very weak reticular shagreening; maxillary palpus with segments in ratio of about 1.2:1.3:1.0:1.2:1.0:1.7, segment 6 nearly round in cross-section; labial palpus with segments in ratio of about 2.0:1.0:1.0:1.6; clypeus twice as broad as long, protruding beyond lower margin of eye by half width of eye in lateral view, shagreening very weak, absent in center, punctures sparse, weak in center, laterally punctures becoming close, distinct; genal area with process at base of mandible tooth-like rather than finger-like; vertex less elevated along posterior margin behind ocelli, extending past lateral ocellus by one ocellar distance.
Mesosoma as in vandykei except: suture extending vertically from leg base ending below humeral angle; parapsidal line short, indistinct; propodeum less sloping, more like female vandykei; pterostigma large, half as wide as prestigma; first transverse cubital vein ending several vein widths from pterostigma.
Metasoma as in vandykei except sternum 6 with apical margin emarginate, flexed downward medially.
Terminalia identical to californiensis (figs. 100-104).
VESTITURE. — Hairs as in vandykei except: fewer chocolate brown hairs on head; thorax with all white hairs; facial fovea weakly developed.
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