Masoniella flabella

Masoniella flabella

DIAGNOSIS.—This species is distinguished from congeners by the following combination of characters: body entirely shiny brown, thorax with a light dusting of microtomentum; frons mostly yellow, dorsal concolorous with ocellar triangle, with a few minute setulae; parafrontal setae sparse, minute; fronto-orbital seta 1, reclinate; ocellar triangle shiny brown; antenna mostly orange with dark area near base of arista; oral vibrissae small, weak; gena 0.10–0.20 times eye height; acrostichal setulae minute, sparse; wing crossveins not infuscate; tarsomeres of normal size; forecoxa white in base color with white microtomentum; mid- and hindfemora not swollen; forefemoral anteroventral ctenidial comb of setae short, individual setae relatively strong.

DESCRIPTION.—Body length 1.85–2.50 mm; body shiny brown with a light dusting of microtomentum.

Head: Ocellar triangle with shiny brown microtomentum only in area between ocelli; frons mostly yellow, concolorous with ocellar triangle dorsally, with a few minute setulae; parafrons with silvery microtomentum at extreme margins; frontal lunule diminutive, yellow; fronto-orbital seta 1; parafrontal setae minute, sparse; ocellar seta 1, well developed, with a few short, weak setulae; paravertical setae minute, convergent. Antenna mostly orange, 1st flagellomere orange with small dark area around base of arista. Gena 0.10–0.20 times eye height, with whitish microtomentum and bearing a few minute, scattered setulae and a row of peristomal setulae; face whitish; shiny chitinous stripe along parafacial and peristomal margins; palpus white; clypeus yellow.

Thorax: Mesonotum entirely shiny brown with a light microtomentum; acrostichal setulae lacking or minute, sparse. Wing hyaline; costal section ratios 6.5:1.5:1.0. Forecoxa white in base color, with whitish microtomentum, with 2 or 3 large setae in addition to a few smaller ones; mid- and hindcoxae with yellow microtomentum; forefemur with only slight swelling in middle, mostly brown with extreme base with yellow microtomentum and bearing posterodorsal row of setae relatively weak, distal 3 or so slightly stronger, posteroventral row short except for distal 2 or 3, many scattered smaller setae on remainder of posterior surface, otherwise evenly setulose; forefemoral anteroventral ctenidial comb with fewer setae than that of most species of Pelomyia, but individual setae relatively strong, shorter than width of foretibia; hindfemur not swollen; mid- and hindfemora with yellow microtomentum, evenly setulose, anterior surface of midfemur with 1 stronger seta in middle; foretibia black, mid- and hindtibiae yellow, microtomentose, evenly setulose; foretarsus brown, mid- and hindtarsi with basal 3 tarsomeres yellow, remainder brown.

Abdomen: Uniformly shiny brown. Male terminalia (Figures 66, 67): ventral lobe of epandrium tapering to a short, blunt point posteriorly, medial surface with a few short, weak setulae; surstylus nearly as long as ventral lobe, narrow, sparsely setulose; aedeagus long, strap-like, narrowed apically, micropubescent over entire length; pregonite fused with hypandrium, leaving only a few setulae on hypandrium; hypandrium stout in lateral view; distal portion of postgonite much reduced, not evident; basiphallus rounded; ejaculatory apodeme with an elongated wide flare. Female terminalia: cercus bearing fine setulae.

TYPE MATERIAL.—The holotype male is labeled “ARGENT[INA]. Salta[:] Rio Juramento, 60km. S. Guemes, 18.X.68. [18 Oct 1968] [L.E.] Pena/HOLOTYPE Masoniella flabella Foster & W.N.Mathis [red label; species name and ‘ and Foster &’ handwritten].” The holotype is glued directly to the pin, is in excellent condition, and is deposited in the CNC.

Two paratypes (1, 1; CNC) bear the same label data as the holotype. Other paratypes are as follows: ARGENTINA. Jujuy: Agua Caliente (NE Guemes; 1100 m), 18–19 Oct 1968, L.E. Peña (1; CNC). Salta: Anjuana (3 km N San Carlos), 5 Oct 1968, L.E. Peña (1, 3; CNC); El Carmen (27 km S Molinos; 1900 m), 6 Oct 1968, L.E. Peña (2, 1; CNC); Rio San Lucas (N San Carlos; 1800 m), 5–6 Oct 1968, L.E. Peña (1; CNC).

BOLIVIA. Cochabamba: Cochabamba (17°23.3′S, 65°07′W; 2610 m), 25 Mar 2001, A. Freidberg (3, 6; USNM).

OTHER SPECIMENS EXAMINED.—ARGENTINA. Salta: Rosário de Lerma (Malaise trap), 16–28 Feb 1992, S.A. Marshall (1; GUE).

BOLIVIA. Santa Cruz: Pampa Grande (swamp), 2 Oct 1996, Bettella and Rossi (1; GUE).

DISTRIBUTION (Figure 74).—Neotropical: Argentina (Jujuy, Salta), Bolivia (Cochabamba, Santa Cruz).

ETYMOLOGY.—The species epithet, flabella, is of Latin derivation and alludes to the fan-like ejaculatory apodeme of this species.