Megachile (Argyropile) rossi Mitchell

Gonzalez, Victor H. & Griswold, Terry L., 2007, A review of the North and Central American Megachile subgenus Argyropile Mitchell (Hymenoptera: Megachilidae), Zootaxa 1461, pp. 1-14 : 5-6

Megachile (Argyropile) rossi Mitchell

Mitchell 1943a: 14, Ψ. Type locality: Tombstone, Arizona, USA. Type repository: CAS. Ayala et al. 1997: 455 [distribution in Mexico]

Yañez-Ordóñez & Hinojosa-Díaz 2004: 188 [distribution in Mexico]

Description. Male. Body length, 12.3 mm (± 0.26, 11.2–13, n = 8); forewing length, 8.4 mm (± 0.2, 7.5–8.8, n = 6). Structure. Head 1.6 times as wide as long; inner orbits converging below, upper interocular distance 1.2 times greater than inferior interocular distance; interalveolar distance 1.4 times longer than alveolorbital distance, the latter about 2.5 times diameter of antennal socket; interocellar distance 2.4 OD, about as long as ocellocular; ocelloccipital distance 1.2 times longer than interocellar distance, about 2.8 times greater than OD; compound eye about 2.1 times as long as wide; gena slightly narrower than width of compound eye in profile; clypeus about twice as broad as long, gently protuberant and convex in profile, apical margin as in Fig. 23 ; mandible tridentate as in Figs. 15–17 ; scape 2.5 times longer than broad, pedicel slightly wider than long, about as broad as F1–F3, individually; F1 slightly longer than broad, about 1.3 timer longer than pedicel, shorter (0.7 times) than F2 and F3, individually. Front coxal spine small, slender, acute, slightly curving anteriorly in lateral view ( Fig. 26 ); fore femur compressed antero-posteriorly, 2.4 times longer than wide, dorsal margin almost straight, ventral margin broadly convex, carinate; fore tibia 0.8 times length of femur, somewhat compressed, about 2.5 times longer than wide; basitarsi of all legs slender and unmodified; hind tibia 3.4 times longer than wide; hind basitarsus about 3.3 times longer than wide, about half tibial length. T6, T7, S4– S6, S8, genitalia as in Figs. 29, 31, 34, 37 , 40, 43, 46, 49 . Coloration. Black, except: apex of mandible, flagellum, legs dark reddish brown; tegula, wing veins yellowish ferruginous; wings subhyaline. Pubescence. White, except apex of anterior surface of front coxal spine, inner surface of tarsi of all legs, inner margins of fore and mid tibiae with ferruginous setae. Basal third of mandible densely covered with very short (<0.5 OD), minutely branched setae, lower margin with longer (> 2 OD) setae; face with dense (integument not visible), long (> 2 OD), minutely branched setae; area above ocelli, vertex with shorter setae than on face, intermixed with some light ferruginous setae; outer surface of scape with dense, long (> diameter of scape), minutely branched setae; upper half of gena with sparse, short (<OD) setae, denser, longer (> 2 OD) on lower gena. Mesosoma with long (> 2 OD), dense setae (integument visible) as on face, shorter, sparser on mesoscutum; mesoscutal-scutellar groove with dense, very short (<0.5 OD), minutely branched setae forming a fascia. Fore leg with coxa, lower margin of trochanter, posterior margin of femur, basitarsus, first tarsomere with long, dense (> 2 OD) setae, longer, denser than on other legs. Sides of T1 and T5, apical margins of T2–T4 and base of T6 except for median projection, with dense, appressed, very short (<0.5 OD), minutely branched setae; S1–S4 and remainder of terga with sparser, erect, whitish to pale grey setae, longer on sterna and sides of terga; longest (> 2 OD) and densest on T1. Punctation. Clypeus finely, closely (1 PW) punctate throughout, except for apical margin smooth, shining; paraocular and supraclypeal areas with smaller, closer punctures than clypeus, integument otherwise smooth, shiny; ocellar area, vertex, gena with coarser, larger, sparser (> PW) punctures than on face, integument otherwise imbricate. Mesoscutum, mesoscutellum as vertex, but punctures slightly larger, coarser; mesepisternum, metepisternum, sides of propodeum coarsely punctate, punctures larger, closer (<0.5 PW) than on mesoscutum; basal area of propodeum minutely rugose. Terga densely (<PW), coarsely punctate, integument otherwise weakly imbricate to lineolate, punctures closer, coarser on T6. S1 and S2 finely, closely (<PW) punctate, discs of S3, S4 with shallow, sparser (1–2 PW) punctures, except for premarginal area of S4 coarsely, densely (<0.5 PW) punctured, almost rugose; S1–S4 with thin, impunctate, translucent, narrow (<OD) marginal zones ( Fig. 29 ).

Material examined. MEXICO. Chihuahua: 4♂, Reserva Biosfera Mapimi, dunes N estacion., E of Ceballos, 22 Aug 1991, T. Griswold; 3♂, 65 km NE of Ceballos, 21–23 Aug 1991, ex: Larrea tridentata (Zygophyllaceae) , R. L. Minckley. Coahuila: 1♂, Zapata, 9 km W, 25 Aug 1991, ex: Verbesina encelioides, R. L. Minckley. Durango: 1♂, Canutillo, 8 mi S, 9 Aug 1951, H. E. Evans [ SEMC].

Distribution. Southwestern United States to northern Mexico.

Floral records. Aster , Baileya multiradiata , Bebbia juncea , Bidens , Cercidium— Caesalpiniaceae , Encelia virginensis , Ericameria nauseosa nauseosa , Eriodictyon— Hydrophyllaceae , Helianthus annuus , Heliomeris multiflora , Larrea tridentata— Zygophyllaceae , Psorothamnus scoparius— Fabaceae , Senecio flaccidus , S. sparttioides , Verbesina encelioides , Viguiera .

Figures

FIGURES 1 – 24. Mid tarsomeres of females (1, 2); male mid tibial spur (3); female mandible (4, 5); sternum six of female, ventral and lateral views (6, 7); apical margin of clypeus of females (8, 9); apex of sternum six (close-up of selected area in Fig. 7) in lateral view (10, 11); superior, lateral and inferior views of male mandible (12 – 20), detail of lacinia of female and male mouthparts (21), and apical margin of clypeus of males (22 – 24). M. flavihirsuta (28); M. longuisetosa sp. nov. (1, 3, 4, 6 - 8, 12 – 14, 21, 22); M. rossi (9, 11, 15 – 17, 23); M. sabinensis (10, 18 – 20, 24).

FIGURES 25 – 38. Fore coxa (25 – 27), sterna four (28 – 29), and five (30 – 32) of males. Terga six, dorsal and ventral views (33 – 35) and seven, dorsal view (36 – 38) of males. M. flavihirsuta (28); M. longuisetosa sp. nov. (25, 30, 33, 36); M. rossi (26, 29, 31, 34, 37); M. sabinensis (27, 32, 35, 38).

FIGURE 39 – 50. Male genitalia and associated sterna. Sternum six (39 – 41), genitalia, dorsal and ventral (42 – 44), and lateral views (45 – 47), and sternum eight (48 – 50). Megachile longuisetosa (39, 42, 45, 48); M. rossi (40, 43, 46, 49); M. sabinensis (41, 44, 47, 50).