Reprinted with permission of the American Entomological Society from:
Ribble, D. W. 1974. A revision of the bees of the genus Andrena of the Western Hemisphere. Subgenus Scaphandrena. Transactions of the American Entomological Society 100: 101-189.
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This species is closely related to A. scurra. In fact, it is as closely or more closely related to scurra than is A. capricornis or A. arabis which interbreed with scurra (Ribble, 1973). Andrena mohavensis is in many respects between scurra and capricornis: hairs on thoracic dorsum and length of scopal hairs in the female, and tip of penis valve, clypeal color and extent of light yellow maculation on parocular area in the male. Andrena mohavensis is considered a separate species because no intermediates have been found and it has several characters not possessed by scurra or capricornis'. tergum 1 of female with partial apical band of hairs, a smooth propodeum like A. mackieae or A. lomatii in both sexes, and penis valve with tiny dorsal lamellae, tip of gonocoxite with curved point and light yellow maculation on supraclypeal area in the male.
Andrena mohavensis appears to be allopatric with scurra and its hybrids. Perhaps competition with mohavensis accounts for the scurra/capricornis /arabis complex or their hybrids presence in the other deserts of the southwestern United States but not the western Mohave Desert.
The descriptions below are based mainly on the holotype and the allotype.
FEMALE. — MEASUREMENTS AND RATIOS. — Length, 9.5 mm; width, 2.8 mm; wing length, 6.4 mm; FL/FW, 0.92; FOVL/FOVW, 4.50.
INTEGUMENTAL COLOR. — Color as in scurra except dorsal part of head with metallic luster, hind legs entirely dark.
STRUCTURE. — Antenna as in scurra. Eyes each about 3.7 times as long as broad, inner margins as in scurra. Mandible, galea, stipes and labial palpus as in scurra but ratio about 1.0:0.4:0.4:0.9. Maxillary palpus as in scurra but ratio about 1.0:1.0:1.0:0.7:0.6:0.7. Labrum as in scurra but process small and apex not emarginate. Supraclypeal area and face above antennal fossae as in scurra. Facial fovea as in scurra but separated from lateral ocellus by about one and one-half ocellar diameters. Vertex and genal area as in scurra.
Pronotum as in scurra. Mesoscutum as in scurra but entire surface with reticular shagreening hiding punctures. Scutellum as in scurra. Propodeum with dorsal area triangular with coarse but regular shagreening; remainder of propodeum as in scurra but shagreening on dorsolateral and posterior surfaces smoother and regular. Mesepisternum as in scurra. Wings as in scurra but vein 1st m-cu meets second submarginal cell near middle of cell. Tarsal claws with moderate sized, inner, subapical tooth; hind tibia as in scurra.
Terga 1-4 as in scurra but apicolateral elevations weak, punctures less distinct. Pygidial plate U-shaped, shagreened; internally nearly flat; margins abruptly upturned. Sterna as in scurra but punctures smaller.
VESTITURE. — Generally white otherwise as in scurra except as follows: hind tibia with dark hairs at base, hind femur at apex and tip of abdomen with amber hairs; thoracic dorsum with hairs slightly shorter; tibial scopal hairs of moderate length at apex; apical white fasciae present laterally on tergum 1, on tergum 2 thinner medially.
MALE. — MEASUREMENTS AND RATIOS. — Length, 7.0 mm; width, 1.9 mm; wing length, 5.6 mm; FL/FW, 0.97; FS1/FS2, 1.40.
INTEGUMENTAL COLOR. — Black to dark brown with same exceptions as female except clypeus cream-colored except apex, parocular area with large spot of color along clypeus, supraclypeal area with small spot of color.
STRUCTURE. — Antenna, eyes, mandible, stipes and galea as in scurra. Labial palpus as in female but ratio about 1.0:0.7:0.5:0.7. Maxillary palpus as in female but ratio about 1.0:1.0:1.0:1.0:0.8:0.8. Labral process small, trapezoidal, deeply notched at apex; labrum below process as in scurra. Clypeus as in scurra but punctures separated mostly by less than one puncture width. Supraclypeal area, face above antennal fossae, vertex and genal area as in scurra.
Pronotum and mesoscutum as in female. Scutellum sculptured as mesoscutum. Propodeum and mesepisternum as in female. Wings as in female but second submarginal cell narrower anteriorly. Legs as in scurra but hind tibia rather slender.
Metasomal terga 1-4 as in female but punctures separated by about three puncture widths. Tergum 5 and sterna 2-6 as in scurra.
Terminalia as in figures 24-28; note the following: gonocoxite with dorsal lobes short and broadly rounded, apex rather narrow and emarginate subapically on inner margin; penis valve rather narrow, dorsal lamellae reduced to tiny elongate lobes, apex short in ventral view, thick, broadly rounded, slightly expanded; sternum 7 with large apical notch; sternum 8 twice bent in side view, with apex slightly broader than neck region in top view, apex notched, with tiny ventral subapical elevation.
VESTITURE. — White otherwise as in scurra except hairs on terga 2-5 more decumbent, apical white fasciae on terga 1-4 weakly developed, broadly interrupted on terga 1 and 2, especially weak in center on tergum 3 and tergum 4.
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