Extracted from: McGinley R. J. (2003). Studies of Halictinae (Apoidea: Halictidae), II: Revision of Sphecodogastra Ashmead, Floral Specialists of Onagraceae. Smithsonian Contributions to Zoology No. 610, pp. 1-54.
Appears as Sphecodogastra potosi in this excerpt.
DIAGNOSIS.—The presence of short, adpressed hairs on the pleuron (e.g., Figure 21) combined with the broad head and elongate mandibles (Figure 18) will distinguish the females of S. potosi from other Sphecodogastra species having dark abdo-mens. For further details, see "Diagnosis" for S. lusoria.
Males of S. potosi can be identified by their darkly pigmented mandibles; mandibles of other congeneric males have conspicuous areas of yellow pigmentation. Other helpful characteristics for recognizing the males of this species are the lack of antennal scnsillar patterns (found in the very common S. lusoria as well as S. antiochensis. Figures 42, 76) and the relatively broad head (Figure 130).
DESCRIPTION.—FEMALE: (1) Length 7.2-8.5 mm (mean = 8.0, n = 5); (2) wing length 2.3-2.5 mm (mean = 2.4, n = 5); (3) abdominal width 2.2-2.6 mm (mean = 2.4, n = 5).
Structure: (4) Head broad (Figure 129); length/width ra¬tio 0.90-0.92 (mean = 0.91, « = 5). (5) Gena, at midpoint, ex¬ceeding width of compound eye. (9) Clypeus projecting ap¬proximately 0.63 times its length below lower margin of eyes; (11) clypeal surface without median longitudinal sulcation. (13) Ocular-ocellar distance subequal to distance between lat¬eral ocellus and hind margin of vertex (ocular-ocellar space approximately 2.0 times lateral ocellar diameter); (14) distance between lateral ocelli slightly exceeding ocular-ocellar dis¬tance. (16) Inner margins of compound eyes nearly parallel. (21) Scape reaching top of vertex; (22) pedicel subequal in length to flagcllomere 1. (30) Mandible elongate, reaching slightly beyond opposing clypeal angle (Figure 18).
(40) Dorsal surface of propodeum about 0.78 times the length of scutcllum and approximately 1.38 times the length of metanotum; (44) lateral propodeal carinae well developed, ex-tending to dorsal propodeal surface. (45) Inner hind tibial spur with 4 or 5 moderately elongate teeth (Figure 63).
(46) Lateral edge of metasomal T2 broadly rounded.
Sculpture: (51) Supraclypeal area polished, (52) punctation only moderately dense, most punctures separated by 1-2 times their diameters. (53) Clypeus polished; (54) apical punctures slightly larger than basal ones, separated by 2-A times their di-ameters. (55) Hypostoma weakly striolate throughout.
(56) Mesoscutum mostly shiny and polished, tessellation confined to the anterior half, (57) punctation as in Figure 134, most punctures separated by 2-3 times their diameters (some-what more sparse than other species). (63) Dorsal surface of propodeum entirely rugulose (Figure 133), (64) surface alvco-lated. (65) Tl shiny and polished, (66) punctation extremely fine, moderately sparse, punctures separated by 1-3 times their diameters.
Coloration: (67) Abdomen dark brown. (69) Flagellum dark brown. (70) Tegula brown. (71) Wing membrane hyaline; veins and stigma light brown. (72) Legs brown.
Vestiiure: (74) Hairs on head white. (75) Pubescence on thorax white; (76) mesoscutal hairs moderately short, length subequal to diameter of median ocellus; mesoscutum and espe-cially pteuron, with short, adpressed hairs. (81) Basal hair bands on T2-T4 presenl, covering basal one-fourth of tergal surface; moderately developed apical hair bands present on T3 and T4.
MALE: As described for female except as follows: (1) length 6.6-7.8 mm (mean = 7.2, n = 5); (2) wing length 1.8-2.1 mm (mean = 2.0, n = 5); (3) abdominal width 1.5-1.8 mm (mean = 1.7, n = 5). (4) Head (Figure 130) length/width ratio 1.04-1.08 (mean = 1.05, n = 5). (23) Flagellomere 2 approxi¬mately 1.5 times length of flagellomere 1. (37) Median meso-scutal line only faintly impressed. (70) Tegula yellowish brown. (73) Short, adpressed hairs on face extending dorsad just below median ocellus. (76) Mesoscutum with both moder¬ately elongate and short, adpressed hairs; pleuron with some short, suberect to adpressed hairs.