Mesoxaea rufescens Hurd & Linsley 1976

South. Ariz.; Mexico (Nayarit, Sinaloa and Sonora).

Mesoxaea rufescens

Oxaea tristis.—Authors [not Gribodo, 1894].—Cockerell, 1906a:72 [Arizona: San Bernardino Ranch]; 1906b:314 [Arizona: Douglas].

Protoxaea tristis.—Authors [not Gribodo, 1894].—Cockerell, 1934b: 153 [Arizona: San Bernardino Ranch and Douglas].— Linsley, 1951:1086, [Mexico and Arizona].

GEOGRAPHIC RANGE (Map 2).—Southwestern United States (Arizona) and adjacent northwestern Mexico (Nayarit, Sinaloa, and Sonora).

MALE.—Length 15–19 mm. Length of forewing, including tegula, 13–15 mm. Head and body chiefly black; metasomal terga feebly metallic blue green, most evident on apical marginal depressions in bright light; antennae dark reddish brown to brownish black, except apex of scape narrowly, and pedicel and first flagellar segment nearly always red or reddened; mandibles black, usually reddened on basal half; clypeus black, normally narrowly reddened apically and sometimes all or much of median surface also reddened; wings dissimilar in coloration, forewings hyaline on about basal two-thirds, apical third darkly infuscated with brownish black, hind wings very nearly hyaline throughout, scarcely and only faintly infuscated apically; wing veins mostly reddish brown, apical veins beyond closed cells darker; tegulae testaceous, darkened to brownish black basally; legs dark brownish black basally, tarsi reddish brown; tibial spurs reddish brown; claws deep mahogany red, banded medially with black.

Vestiture of head chiefly ochraceous (nearly white in older specimens), usually becoming pale fulvo-ochraceous above antennal sockets and often turning to brownish black on upper part of face and vertex; hind margins of head chiefly or entirely ochraceous (paler in older specimens), sometimes intermixed dorsally with a few brownish black hairs; thorax thickly clothed with fulvo-ochraceous pubescence throughout (paler in older specimens), usually paling to ochraceous on sides and ventrally; legs chiefly ochraceous to reddish brown pubescent, palest basally, darker on tarsi and nearly brownish on hind femora ventrally; pubescence of first metasomal tergum consisting of long, whitish plumose hairs, thickest at sides and ventrally, not darkened to black on raised submarginal areas laterally; metasomal terga II–IV without apical bands of pale pubescence, mostly clothed with short, posteriorly directed, brownish black pubescence, longest and thickest at sides; tergum II tufted with white pubescence on ventrally exposed sides and with shorter and less conspicuous, erect white hairs on discal surface medially at base; metasomal terga III and IV tufted with long, whitish pubescence on extreme ventrally exposed sides; metasomal tergum V entirely brownish black or black pubescent, shortest on punctate surface basally, much longer and forming a transverse band of simple hairs arising just before impunctate apical margin, projecting posteriorly and terminating in thick tufts of plumose hairs laterally; metasomal tergum VI with numerous long, posteriorly directed, white plumose hairs arising just before impunctate apical margin, longest and somewhat tuftlike laterally, usually intermixed on median tergal surface with brownish black or black hairs; metasomal tergum VII with pubescence chiefly white and disposed laterally as posteriorly projected tufts of plumose hairs; metasomal sterna thickly clothed with rather long, plumose hairs, usually white or cinereous on sterna I–III, and on terga IV–VI brownish pubescent basally, but apical hairs white or nearly so.

Eyes moderately convergent above, separated on vertex by about or more than minimum distance between hind ocelli, but always by much less than minimum distance between rims of antennal sockets; clypeus densely, finely and confluently punctured on sides, punctures on median surface larger, coarser, and separated by shining interspaces on lower half, except medial margin apically almost impunctate, smooth, and reddened; supraclypeal area, except above, densely and confluently punctured, without shining interspaces; frontal carina somewhat triangular in outline, deeply excavated basally, nearly as long as diameter of median ocellus; middle tibiae and basitarsi of equal length; punctation on discs of metasomal terga I and II dense, rather fine with punctures separated by mostly less than their diameters, that on terga III and IV similar, but larger and much less densely disposed, especially medially, and with large impunctate or sparsely punctate areas extending across terga and basal to submarginal depressions; fifth metasomal tergum with discal punctures similar in size and disposition to those on tergum II, but larger and less densely crowded especially medially; structure of seventh metasomal tergum (Figure 45), seventh and eighth metasomal sterna (Figures 46, 47), and genitalia (Figure 48) as illustrated.

FEMALE.—Length 16–20 mm. Length of forewing, including tegula, 14–15 mm. Head and body black, not much paler on metasoma below; metasomal terga feebly metallic blue green with some purplish tints in bright light and most noticeably so on impunctate surfaces; antennae dark brownish black, somewhat reddened at apex of scape, pedicel, and variably below on usually apical flagellar segments; mandibles black, reddened usually at base and occasionally apically; clypeus brownish black to black, not reddened on medial surface; wings dissimilar in coloration, forewings hyaline on about basal two-thirds, apical third darkly infuscated with brownish black, hind wings nearly hyaline throughout, scarcely and only faintly infuscated apically; wing veins mostly reddish brown, apical veins beyond closed cells darker; tegulae testaceous externally, darkening to brownish black basally; legs mostly brownish black to black, somewhat reddened on tarsi and below; tibial spurs dark reddish brown; claws deep mahogany red, banded medially with black.

Vestiture of head chiefly long and white on face, especially that about ocelli antennal sockets, clypeus at sides, becoming brownish black on upper part of face and on vertex; hind margins of head rather thickly and mostly clothed with long whitish pubescence, sparsest and shortest on cheeks, intermixed with and sometimes replaced by dark brownish black pubescence dorsally near and on vertex; thorax thickly clothed with fulvous pubescence dorsally, paling to ochraceous on metanotum, propodeum, and on lower sides and ventrally; legs chiefly white pubescent basally, darker pubescent, usually reddish brown on exterior surfaces and on tarsi; scopal hairs of hind legs entirely pale, mostly white or nearly so; discal surfaces of metasomal terga I–IV devoid of pubescence except for very short, posteriorly directed, brownish black hairs situated laterally, which at extreme sides and on ventrally exposed surfaces are replaced on terga I and II by scopae consisting of long, densely plumose, mainly whitish hairs and ventroapically on terga III and IV with long tufts of chiefly whitish plumose hairs; metasomal tergum V apically traversed by a thick fringe of long, posteriorly directed, plumose hairs characteristically white at sides and brownish black on median tergal surface; metasomal tergum VI densely clothed on either side of pygidial plate with moderately long, mostly brownish black plumose hairs, sometimes at extreme sides with a few white hairs; scopal hairs of metasomal sterna I–III white; other surfaces of metasomal sterna II–V (except at extreme sides) and VI thickly clothed with rather short to moderately long, posteriorly directed, reddish brown to brownish black hairs; extreme sides of metasomal sterna II-V with long tufts of white plumose hairs projecting posteriorly from under overlapping tergal surfaces.

Eyes weakly diverging below (46:51); clypeus, except narrowly impunctate mediolateral corners, coarsely, rugosely, and nearly confluently punctate throughout; supraclypeal area, except narrowly impunctate sides, about as coarsely punctate as clypeus; frontal carina narrowly triangular in outline, deeply excavated, slightly longer than maximum diameter of median ocellus; discal surfaces of metasomal terga I–V basal to marginal depressions deeply and coarsely punctured, punctures well separated medially, crowded laterally, sparsest on tergum I and closest and densest on tergum V.

TYPES.—Holotype male was collected 5.3 miles west of Pena Blanca Lake, Santa Cruz County, Arizona, on 29 July 1972 from the flowers of Acacia angustissima (Fabaceae) between 1000–1100 (Mountain Standard Time) by T. J. Zavortink, and is deposited in the collections of the California Academy of Sciences, San Francisco. The allotype female was collected one mile east of Douglas, Cochise County, Arizona, and 20 August 1962, from the flowers of Verbesina encelioides by M. A. Cazier and is deposited in the collections of the California Academy of Sciences.

SPECIMENS EXAMINED, (paratypes).—United States. Arizona. Cochise County: San Bernardino Ranch, Douglas, 3700 ft, , , August (F. H. Snow, CU, PHT); , same data (N. Banks, MCZ). Hereford, , VII–4–58 (Diane Luther, UCD). Santa Cruz County: Pena Blanca Lake, 9.5 mi WNW Nogales, 4000 ft, , VIII–18–74, from the flowers of Kalhtroemia grandiflora, 0915–0930 MST (T. J. Zavortink, TJZ); , same data, except VIII–20–74, 0945–1000 MST (T. J. Zavortink, TJZ); 3 , same data, except 1015–1030 MST (T. J. Zavortink, TJZ).

Mexico. Nayarit: Acaponete, 4 mi S, 2 , 5 , IX–2–62 (D. H. Janzen. CIS). Arroyo Santiago, near Jesus Maria, 2, VII–5–55 (B. Malkin, CIS). Jesus Maria, , , VI–26–55 (B. Malkin, CIS). San Bias, 17 mi E, , VII–20–53 (University of Kansas Mexican Expedition, KU). Tepic, 18 mi N, , VIII–16–60 (P. H. Arnaud, E. S. Ross, and D. C. Rentz, CAS). Sinaloa: Campana, 16 mi NW on Hwy 15, , IX–13–64 (A. E. Michelhacher, CIS). Choix, 3.5 mi NW, VII–25–69 (T. A. Sears, R. C. Gardner, and C. S. Glaser, UCD). Choix, 5.5 mi NW, 2 , VII–5–68 (T. A. Sears, R. C. Gardner, and C. S. Glaser, UCD); , VII–25–69 (same collectors, UCD). Concordia, 9 mi E. . VII–7–64 (J. F. McAlpine, CNC). Culiacan, 4, VIII–22–60 (R. L. Westcott, LACM). Culiacan, 50 mi N, , IX–9–72 (W. Hanson, GEB). Culiacan, 6 mi S, , VII–22–54 (M. Cazier, W. Gertsch and Bradts, AMNH). Culiacan, 30 mi S, , 12 , VII–24–73, on flowers of Mimosa polyantha (E. G. and J. M. Linsley, A. E. and M. M. Michelhacher, and J. A. Chemsak, CIS). Culiacancito, 3 mi E, , IX–3–64 (G. R. Noonan, LACM). Elota, 13 mi N, , VIII–14–60 (P. H. Arnaud, E. S. Ross, and D. C. Rentz, CAS). Elota, 18 mi S, , . VIII–7–64, on flowers of Croton ruliacanesis (J. A. Chemsak, CIS). Espinal, 14 mi SE, 3, IX–14–64 (A. E. Michelhacher, CIS). Guamuchil, 4 mi S, , VII–7–64 (J. A. Chemsak. CIS). Guamuchil, 18 mi S, 5, 3, VIII–7–64 (J. A. Chemsak, CIS); 5, 2, same data (J. A. Powell, CIS). Guamuchil, 19 mi SE, , IX–13–64 (A. E. Michelhacher, CIS). Loreto, , VII–17–68 (T. A. Sears, R. C. Gardner, and C. S. Glaser, UCD). Los Mochis, , VIII–9–22 (C. T. Dodds, CAS). Los Mochis, 15 mi W, , VIII–28–66 (E. G. and J. M. Linsley and J. A. Chemsak, CIS). Mazatlan, , , VIII–6–64 (W. R. M. Mason, CNC); , VII–24–65 (W. J. Gertsch and R. Hastings, AMNH); , VIII–9–70 (M. S. and J. S. Wasbauer, CIS); 2, IX–11–70 (G. E. and R. M. Bohart, GEB); , VII–26–72 (A. E. and M. M. Michelhacher and J. A. Chemsak, (CIS). Mazatlan area, , IX–5–71 (W. J. Hanson, GEB). Mazatlan, 2.5 mi N, , VIII–10 to 11–70 (J. A. Chemsak, CIS). Mazatlan, 5 mi N, , VII–27–64, on flowers of Buddleja ivrightii (J. Chemsak, CIS); 4, same data (J. A. Powell, CIS); 21 , 2, VII–29–73, on flowers of Turnera difjusa (E. G. and J. M. Linsley, A. E. and M. M. Michelhacher, and J. A. Chemsak, CIS). Mazatlan, 9 mi N, . 9, VII–25 to 28–72, on flowers of Solanum sp. (J. A. and M. A. Chemsak and A. E. and M. M. Michelhacher, CIS); 5, , VII–26–73 (same collectors). Mazatlan, 35 mi N, , IX–14–64 (A. E. Michelhacher, CIS). Mazatlan, 46 mi NW, , IX–5–71 (W. J. Hanson, GEB). Villa Union, 100 ft, , VII–20–53 (University of Kansas Mexican Expedition, KU). Villa Union, 3 mi E, , , VII–24–72 (J. A. and M. A. Chemsak and A. E. and M. M. Michelhacher, CIS). Sonora: Alamos, , VIII–10–52 (P. and C. Vaurie, AMNH); , IX–1–60 (R. L. Westcott, LACM); 2 , IX–7–70 (G. E. and R. M. Bohart, GEB); , IX–5–70 (R. M. Bohart, UCD). Alamos, W, 6, IX–4–70 (W. J. Hanson and T. L. Whitworth, GEB). Alamos, SE, 3, IX–5–70 (W. J. Hanson and T. L. Whitworth, GEB). Ciudad Obregon, , IX–15–70 (E. M. Fisher, LACM). Estacion Llano, 20 mi N, , VIII–17–64 (UCR). Estacion Llano, 19.4 mi S, 700 m, 2, , VIII–25–64 (M. E. Irwin, UCR); , , same data (P. A. Rauch, UCR); 12 , same data (E. I. Schlinger, UCR). Guaymas, , VIII–5–40 (R. P. Allen, CAS); , VI–12–62 (D. H. Janzen, CIS); 2, VIII–31–68 (R. W. Thorp, UCD). Hermosillo, 29 mi N, , VIII–9–60 (D. C. Rentz, LACM). Hermosillo, 40 mi N, , VIII–21–54 (R. E. Ryckman, C. P. Christianson, and D. Spencer, USNM). Hermosillo, 15 mi S, , VIII–21–65 (W. J. Gertsch and R. Hastings, AMNH). Hermosillo, 30 mi S, , IX–3–70, on flowers of Solarium sp. (G. E. and R. M. Bohart, GEB). Navajoa, 3, IX–9–70, on flowers of Solarium sp. (G. E. and R. M. Bohart, GEB). Navajoa, 5 mi E, 2 , IX–9–70 (R. M. Bohart, UCD). Navajoa, 8 mi E, , VIII–28–68 (R. W. and J. T. Thorp. UCD). Navajoa, 13 mi E, , IX–12–64, on flowers of Solarium sp. (A. E. Michelhacher, CIS). Rio Chuchuhagui, 7 mi S, 2, VII–25 to VIII–7–53 (F. S. Truxal, LACM). Rio Mayo, , VIII–10–35 (CIS). San Bernardo, Rio Mayo, 3, , VIII–16–35 (GEB); , VIII–25–35 (UA); 5 , VIII–25–35 (H. S. Gentry, LACM).