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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One series of females represents the known material of this species. Males could not be matched with these females, although there is a possibility that penutiani (known only from males) is the male belonging to these females. Andrena penutiani has a long clypeus but it is a little small to be the male belonging to murietae and has not been collected on the eastern side of the San Joaquin Valley (it has been collected as close as 95 miles W.S.W. in the Coast Range). Andrena penutiani appears more closely related to the males of californiensis than to the males of arctostaphylae. One would expect the converse if it were the male of murietae.
This species is exceedingly similar to arctostaphylae. Both species have the clypeus extending much below the level of the lower eye margins, enough so that the females appear long-headed rather than wide-headed as in vandykei. Andrena murietae has a slightly narrower stigma (with a corresponding lengthening of vein r) than arctostaphylae. The facial foveae are bright brown (when viewed from above) and are not wide. Both vandykei and arctostaphylae have very wide, chocolate brown foveae. The latter two species have long hairs on the dorsum of the thorax while murietae has short, moss-like hairs. The apical serrate part of the anterior tibial spur is long as in vandykei, unlike the short spur of arctostaphylae. The antennae are short as in vandykei, whereas arctostaphylae has slightly longer antennae.
FEMALE. MEASUREMENTS AND RATIOS. — Length, 6.6 mm; width of mesothorax, 1.9 mm; wing length from tegula, 5.3 mm; facial length/width, 1.03; foveal length/width, 3.33.
INTEGUMENTAL COLOR. — Color as in vandykei except: flagellum orange below; terga with broad amber apices, terga otherwise dark brown to black.
STRUCTURE. — Head as in vandykei except: scape reaching to within one ocellar distance from middle ocellus; flagellar segment 1 shorter than 2 and 3 together; segment 2 equal to 3 in length; mandible extending slightly past midline, apex rounded, subapical tooth reduced to rounded expansion of mandible (the mandibles appear worn and may be more like vandykei in fresh specimens); galea partly covered with extremely fine, widely spaced, reticular shagreening; maxillary palpus with segments in ratio of about 1.0:1.4:1.1:1.6:1.3:1.4; labial palpus with segments in ratio of about 2.1:1.0:1.0:1.4; labrum about twice as wide as long; process three-fourths as wide as entire labrum, process broadly subtriangular; clypeus extending ventrally past level of lower eye margins; genal area in lateral view slightly wider than eye; facial fovea dorsally slightly narrower than eye.
Mesosoma as in vandykei except: deep suture crossing base of posterior pronotal lobe ending below humeral angle; scutellar surface very shiny, with minute reticular shagreening in center; pterostigma large, nearly twice as wide as prestigma; first transverse cubital vein ending three vein widths from pterostigma.
Metasoma as in vandykei.
VESTITURE. — Hairs as in vandykei except leg hairs mostly white, fovea bright brown viewed from above, some light amber hairs on tarsi, tibiae and tip of hind femur; dorsum of thorax with short, plumose hairs, branches close together, thorax having a moss-like appearance; apical abdominal fasciae weak but distinct on terga 2 and 3, very weak on 4.
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