Reprinted with permission of the American Entomological Society from:
LaBerge, W. E., Ribble, D. W. 1975. A revision of the bees of the genus Andrena of the Western Hemisphere. Part VII. Subgenus Euandrena. Transactions of the American Entomological Society 101: 371-446.
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This moderate-sized dark bee is very similar in appearance to Andrena nigrocaerulea. It differs from nigrocaerulea in the longer maxillary and labial palpi and the longer clypeus, as well as being somewhat larger in size. In addition, both sexes of lawrencei have longer vertices and lack metallic reflections or these are extremely faint.
FEMALE. MEASUREMENTS AND RATIOS. — N = 20; length, 10-12 mm; width, 3-4 mm; wing length, M = 3.95 ± 0.120 mm; FL/FW, M = 1.12 ± 0.097; FOVL/FOVW, M = 3.30 ± 0.059.
INTEGUMENTAL COLOR. — Black, often with faint, dark blue metallic reflections on face above clypeus, thoracic dorsum, and terga 1-4; tergal apical areas often dark reddish-brown; mandible with apical half or more rufescent; flagellum reddish-brown below; clypeus without violaceous reflections; wing membranes slightly infumate, yellowish; veins dark reddish-brown to red; tibial spurs dark reddish-brown; sterna slightly rufescent, usually without metallic reflections.
STRUCTURE. — Antennal scape as long as first three and one-third flagellar segments; flagellar segment 1 about as long as next two and one-half segments; segment 2 about as long as 3 and each slightly shorter than 4 and about as broad as long or slightly broader; segments 4-9 quadrate or slightly longer than broad. Eyes each about four and one-half times as long as broad, inner margins parallel or converging slightly towards vertex. Mandible of moderate length, at rest barely reaching far corner of labrum; with subapical tooth. Galea pointed, moderately broad (lateral surface evenly convex to straight), surface lightly reticularly shagreened. Maxillary palpus long, segmental ratio about as 1.0:1.4:1.2:1.1:0.8:0.8. Labial palpus with long curved first segment slightly flattened apically, palpus as long as first five segments of maxillary palpus; segmental ratio about as 1.6:1.3:0.9:1.0. Labral process large, trapezoidal, narrowly emarginate apically to form two small acute teeth; labrum below process rounded except shallow apical groove, without cristae or punctures. Clypeus elongate, in facial view extending forward beyond a line at lower ends of eyes by more than half median length of clypeus; with small round punctures separated by half to one puncture width, sparser along midline; surface shiny, reticular shagreening absent or fine except basally. Supraclypeal area with minute crowded punctures and shagreening dulling surface Face above antennal fossae with longitudinal rugulae diverging towards ocelli and inconspicuous interrugal punctures. Facial fovea small, extending below usually not quite to level of lower margins of antennal fossae, separated from lateral ocellus by about one ocellar diameter or slightly more. Vertex above lateral ocellus equal to about one ocellar diameter, dulled by course shagreening and line punctures. Genal area in profile distinctly broader than eye (about as 5:3); surface dulled by obscure minute punctures and fine reticular shagreening.
Pronotum moderately shiny. reticularly shagreened and sparsely punctate. Mesoscutum opaque; small punctures separated by one puncture width or more obscured by coarse, irregular tessellation; parapsidal line of moderate length, about as long as from its posterior end to margin of scutum. Scutellum and metanotum similar to mesoscutum but punctures more evident on scutellum. propodeum with dorsal area tessellate except minute short rugulae at base; dorsolateral and posterior surfaces with large shallow punctures obscure, surface coarsely and regularly tessellate. Mesepisternum similar to propodeal posterior surface but tessellation finer and punctures deeper, especially below. Wing with pterostigma long, narrow, about as broad as from inner margin prestigma to wing margin; vein 1st m-cu meets second submarginal cell near middle of cell; hind wing with broad, long; vannal lobe. Tarsal claws normal; hind tibia only moderately broadened towards apex.
Metasomal terga with distinct small punctures even in apical areas, punctures separated mostly by two to three puncture widths, apical area punctures smaller and sparser; surface shiny to moderately so, with fine, transversely reticular shagreening. Pygidial plate V-shaped with rounded apex, internal triangle not raised or extremely slightly so. Sterna 2-5 dull with coarse punctures in apical halves (except narrow apical margin), impunctate at base, with coarse reticular shagreening.
VESTITURE. — Black except as follows: face above antennae and vertex with ochraceous hairs; genal area often with ochraceous hair; thoracic dorsum and tegulae will bright ochraceous hairs: tergum 1 and usually base of tergum 2 often with sparse, ochraceous hairs. Pollen-collecting hairs as in nigrihirta. tibial scopal hairs always simple. Sterna 2-5 without subapical pale fimbriae.
MALE. MEASUREMENTS AND RATIOS. — N = 15; length, 10-11 mm; width, 2.5-3.0 mm; wing length (N = 14), M = 3.5S ± 0.200 mm; FL/FW, M = 1.13 ± 0.010; FS1/FS2, M = 1.63 ± 0.031.
INTEGUMENTAL COLOR. — As in female except as follows: mandible with apical third rufescent; terga usually with dark blue, faint, metallic reflections.
STRUCTURE. — Antenna moderate in length, reaching scutellum in repose; scape length equals to first two and one-fourth flagellar segments; flagellar segment 1 only three-fourths as long as segments 2 plus 3 and often slightly shorter; segment 2 about as long as 3 and slightly longer than broad, segments 4-10 longer than 3, distinctly longer than broad. Eyes each about three and one-half times as long as broad, inner margins parallel or converging slightly towards mandibles Mandible and galea as in female. Maxillary palpus as in female but segmental ratio about as 1.0:1.1:1.0:1.0:0.K:1.0. Labial palpus elongate as in female but ratio about as 1.5:1.0:0.9:1.0. Labral process large, almost quadrate, weakly bidentate apically; labrum as in female. Clypeus and supraclypeal area as in female but clypeal punctures deeper and usually more crowded. Face above antennal fossae as in female but rugulae not diverging, parallel. Vertex as in female.
Thoracic sculpturing and wing venation as in female. Hind tibia broad but not twice as broad as basitarsus, surface usually shiny.
Metasomal sculpturing much as in female but tergum 5 similar to 4 and sterna 2-5 with much sparser punctures and shinier. Sternum 6 flat, not reflexed apically, extremely shallowly and broadly emarginate.
Terminalia as in figures 18-19; note the following: genital capsule much as in nigrihirta; sternum 7 with apical lobes more acute than in nigrihirta.
VESTITURE. — Generally as in female except as follows: pale hairs often much paler, ashen; tergum 2 occasionally covered with long sparse ochraceous hairs except a few dark hairs intermixed with the pale apically. Sternal subapical fimbriae absent.
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