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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Andrena hermosa is a colorful little bee which appears to be an isolated species, but can be considered as being more closely related to the vandykei group than to any other Andrena. For this reason hermosa is placed with vandykei in Derandrena, although it is realized that hermosa is at the periphery of the subgeneric limits. Andrena hermosa cannot be conveniently placed in any other existing subgenus and to erect new subgenera for all Andrena as distinct as hermosa would lead to a huge number of monotypic subgenera. It seems best to have an enlarged concept of existing subgenera. Andrena hermosa does have characters which bind it to the vandykei group, some of the more important are: strong humeral angle without a ridge in both sexes, wide head, large pterostigma, small size, cream-colored clypeus in the male, rectangular labrum without a distinct process in the male, narrow tibia with long scopal hairs. The long, plumose hairs on the anterior part of the propodeal scopa would place hermosa nearest to californiensis in the vandykei group. Andrena hermosa also differs from the vandykei group in several respects, the most important of which are: cream-colored parocular areas in the male, very unusual genital capsule, wide sternum eight, metallic reflections, very shiny, unsculptured dorsum of the thorax, wide apex of the galea, more punctate clypeus in the male.
FEMALE. MEASUREMENTS AND RATIOS. Length, 6.2 mm; width of mesothorax, 1.5 mm; wing length from tegula, 4.6 mm; facial length/width, 0.89, foveal length/width, 3.50.
INTEGUMENTAL COLOR. Brown to dark brown except: dorsal part of head and thorax with bluish-black reflections; flagellum yellow below; terga and sterna with broad amber apices, sterna otherwise brown with black splotches; color otherwise as in vandykei.
STRUCTURE. Head as in vandykei except: antenna reaching to tegula; scape reaching to within two ocellar distances of middle ocellus, longer than flagellar segments 1-5; flagellar segment 1 distinctly longer than 2 and 3 together; segment 2 equal to 3 in length, shorter than 4; segment 4 as well as 2 and 3 slightly tapered towards base; middle segments much wider than long; ultimate segment about half again as long as broad; mandible and submandibular tooth rounded; galea with outer margin apically turning rather abruptly to meet inner margin, thus producing a galea with a wider apex than vandykei, surface with minute reticular shagreening; maxillary palpus with segments in ratio of about 1.4:1.6:1.4:1.2:1.0:1.4; labial palpus with segments in ratio of about 2.0:1.0:1.2:1.7; labrum about twice as wide as long, process half as long as entire labrum, broad, subtriangular in shape; entire clypeus with distinct reticular shagreening, punctures moderate in size, indistinct laterally; supraclypeal area with shagreening like clypeus; genal area distinctly wider than eye, shagreening moderate in coarseness; ver¬tex extending past lateral ocellus by less than one ocellar width; facial fovea reaching upper eye margin, dorsally two-thirds width of eye, ventrally fovea narrower than in vandykei.
Mesosoma as in vandykei except: humeral angle distinct, elevated much above dorsolateral surface of pronotum; suture crossing base of posterior pronotal lobe ending below humeral angle; center of mesoscutum very shiny, unshagreened; scutellum very shiny, unshagreened in center; metanotum with an unshagreened area on each side of midline; enclosure of propodeum with shagreening not becoming granular basally; hind tibia slightly widened, about twice as wide as basitarsus; pterostigma large, nearly twice as wide as prestigma; first transverse cubital vein ending about three vein widths from pterostigma; first m-cu vein ending near middle of second submarginal cell.
Metasoma as in vandykei except pygidial plate slightly depressed in center.
VESTITURE. Hairs as in vandykei except: all hairs amber to white in color; propodeal corbicula with few mostly weakly branched hairs on anterior half, posterior half bare; terga 3 and 4 hairs numerous, much branched, these terga having a slight dusty appearance; apical abdominal fasciae distinct on terga 3-4, interrupted medially on 2 and 3, complete on 4.
MALE. MEASUREMENTS AND RATIOS. Length, 6.2 mm; width of mesothorax, 1.4 mm; wing length from tegula, 4.4 mm; facial length/width, 0.78; flagellar segment 1/segment 2, 2.00.
INTEGUMENTAL COLOR. Color as in female except clypeus and parocular area cream-colored.
STRUCTURE. Head as in vandykei except: antenna reaching to posterior part of mesoscutum; scape much longer than flagellar segments 1-4; segment 1 twice as long as 2 or 3; segment 2 and 3 slightly tapered towards bases; middle segments about as long as broad; ultimate segment almost twice as long as broad; inner eye margins slightly convergent below; malar space about eight times as wide as long; mandible moderate in length, not bent in middle, reaching to considerably less than opposite corner of clypeus, apex and subapical tooth rounded, base of mandible without lobe; maxillary palpus with segments in ratio of about 1.4:1.6:1.2:1.2:1.0:1.6; labial palpus with segments in ratio of about 2.0:1.2:1.0:1.7; clypeus two and one-half times as broad as long; protruding beyond lower margin of eye by one-third width of eye in lateral view, punctures close, especially ventrally and laterally; genal area less pointed posteriorly than vandykei, without process at base of mandible, shagreening moderately coarse; vertex moderately elevated along posterior margin behind ocelli, extending past lateral ocellus by slightly more than one ocellar distance.
Mesosoma as in vandykei except: suture extending vertically from leg base ending below humeral angle; propodeum as in female except coarse shagreening laterally; vein r very short.
Metasoma as in vandykei except sternum 6 with large apical emargination.
Sternum 7 weakly trilobed at apex, laterally with few simple setae, sternum unshagreened (fig. 113). Sternum 8 with apical half convex, base much expanded into broad plate (fig. 114); apex much expanded, weakly emarginate; shaft short, bent downward and then posteriorly; sternum with apical half setose, most setae branched, setae not reaching beyond apex. Gonocoxite very broad, rounded, bent downward; gonoforceps expanded near middle, dorsal surface with many simple setae; dorsal lobes wide, long. Penis valve bent anteriorly, apex very broad, much expanded in side view, narrow in ventral view but large dorsal lamellae making valve appear broad (figs. 110-112).
VESTITURE. Hairs as in vandykei except: hairs all white; clypeus with dense beard; apical abdominal fasciae weak; sternal hairs as in female.