Brachylinga albiseta (Malloch)

Webb, Donald W. & Metz, Mark A., 2006, A Revision of the New World Genera Brachylinga Irwin and Lyneborg and Lysilinga Irwin and Lyneborg (Diptera: Therevidae: Therevinae) with the Description of a New Genus, Elcaribe Webb, Zootaxa 1288 (1288), pp. 1-241 : 19-33

Brachylinga albiseta (Malloch)

( Figs. 3, 26, 49, 72, 95, 118, 141, 164, 186, 208)

albiseta Malloch (1932:252 orig. desc.) ( Psilocephala ); Metz et al. (2003:21 comb. change) ( Brachylinga ). Type locality Argentina, Río Negro, eastern end of Lago Nahuel Huapi. Holotype male in BMNH.

Diagnosis

Brachylinga albiseta is taxonomically associated with B. albifrons , B. bicolor , B. cinerea , B. concava , B. curacaoensis , B. divaricata , B. fraterna , B. mimica , B. morata , B. ornata , B. pavida , B. punctifrons , B. tepocae , B. tridentata , and B. xanthoperna in lacking setae on the katepisternum. It differs from these species in having the postocular, mesonotal, and coxal macrosetae dark yellow.

Redescription of male

Variation (n=10).

Body length 3.5–5.1, 4.3 mm.

Head. Ommatidia smaller ventrally and laterally. Frons white (occasionally dark on dorsal fourth); setae white. Antenna dark brown, scape pruinescence gray; setae on scape dark yellow. Parafacial dark reddish brown, glossy surrounded by white pruinescence. Maxillary palpus yellow; setae yellow. Genal setae white. Occipital setae white becoming lanceolate, appressed dorsally. Postocular macrosetae dull yellow.

Thorax. Macrosetae pale yellow (occasionally brown), 3 np, 1 sa, 1 pa, 0–1 dc, 2 sc. Mesonotum dull brown; setae dark yellow, elongate intermixed with white, lanceolate, appressed setae. Pleuron and scutellum dark reddish brown, pruinescence white; setae white on propleuron, anepisternum, metanepisternum, laterotergite, and scutellum, absent on katepisternum. Wing. Membrane pale gray, veins pale brown; veins and crossveins with narrow, brown margin; pterostigma dark brown; cell m 3 closed, petiolate. Halter pale yellow. Legs. Coxa setae white, present on posterior surface of midcoxa; macrosetae pale yellow. Forefemur yellow, midfemur yellow with apex brown, hindfemur yellow with apex and dorsal surface brown; ventral setae white on fore­ and midfemora; av 0:0:1–3, pv 0:0:0. Tibiae dark yellow, apex becoming dark brown. Tarsomeres 1–2 dark yellow, dark brown apically; 3–5 dark brown.

Abdomen. Dark brown, pruinescence gray; dorsal setae white, appressed; lateral setae white, elongate. Terminalia . Reddish brown. Tergite 8 ( Fig. 3), narrow medially (0.05 mm); setae dark yellow, absent medially on posterior margin. Sternite 8 ( Fig. 26), sides parallel; posterior margin emarginate; setae dark yellow. Epandrium ( Fig. 3), sides tapering apically; setae dark yellow. Cercus ( Fig. 3) ending above apex of hypoproct. Hypoproct ( Fig. 3), posterior margin truncate, ending below apex of cercus. Gonocoxite ventral view ( Fig. 26), medial margin rounded then tapering apically to narrow point; setae dark yellow with short, dark yellow setae basomedially, directed ventrally; dorsal view ( Fig. 49), posteromedial lobe absent, gonocoxal bridge small; lateral view ( Fig. 72) oblong, tapered apically to broad, truncated apex; ventral lobe ( Fig. 26) with ventral spines. Gonostylus ( Fig. 95), basodorsal lobe large; ventral margin rounded, setae dark yellow, not extending apically in distinct tuft; mediolateral surface with fine spines. Aedeagus with dorsal apodeme ( Fig. 118) quadrate, anterior margin emarginate; ventral apodeme ( Fig. 141) tapered anteriorly, ending at anterior margin of dorsal apodeme; distiphallus tapered apically ( Fig. 118), lateral view ( Fig. 164) elongate, sinuate, apicolateral spines absent; ejaculatory apodeme ( Fig. 118), anterior margin truncate.

Female

Similar to male except for following.

Variation (n=10).

Body length 4.3–6.0, 5.2 mm.

Head. Frons dull yellowish brown becoming white ventrally with small, ill­defined brown area dorsolaterally; setae white with occasional brown setae. Parafacial dark reddish brown, glossy surrounded by white pruinescence. Maxillary palpus pale brown; setae yellow.

Thorax. Macrosetae 2–3 np, 1 sa, 1 pa, 0–1 dc, 1–2 sc. Mesonotum dull brown; setae white, elongate, subappressed, more abundant on anterior half. Legs. Anteroventral macrosetae 0:0:2–4, pv 0:0:0.

Abdomen. Dark reddish brown, pruinescence white, posterior margin and posterolateral area of tergites 2–7 dark yellow; dorsal setae white, elongate, appressed; lateral setae white, erect. Terminalia . Dark reddish brown, pruinescence white. Furca ( Fig. 186) quadrate, posterior margin rounded, sides parallel, anterior margin truncate; length 0.40 mm, width 0.20 mm; anterolateral projection absent. Common duct ( Fig. 186) shorter than furca. Spermathecal duct ( Fig. 186) diverging laterally from common duct, then directed anteriorly.

Distribution Brachylinga albiseta is known from Argentina ( Fig. 208).

Habitats and phenology

Brachylinga albiseta has been handnetted from November through January. A male (MEI 074531) and female (MEI 110487) were reared from larvae collected near Bajada del Agrio, Rio Agrio from low riverbottom dunes.

Specimens examined

Type specimen. The holotype male of Psilocephala albiseta Malloch is labeled "Argentina, L. Nahuel Huapi, eastern end, 17.xi.1926 " and is in the BMNH. Other specimens. ARGENTINA. CHUBUT. Arroyo Verde [Puerto Lobos], 12 km S Rio Senguer [­42.004, ­65.078], 710 m, 20.XI.1966, EIS, MEI, 3♂ MEI 074528–30 ( MEIC) ; 19.9 km N Malaspina [­44.754, ­66.9], 550 m, 13.XII.1966, EIS, MEI, 9♂ MEI 074500–4, 074506, 074512, 074514–5, 1♀ 074505 ( MEIC) . MENDOZA. Ref. Olvarado [Altos de Olvido] [­ 32.651, ­68.551], 2200 m, 22.I.1950, M. Aczel, 1♂ MEI 045944 ( MEIC) . NEUQUé N. Neuquén [­38.95, ­68.07], 26.XI.1946, Hayward, Willink, 1♂ MEI 045948, 1♀ 045949 ( IMLA) ; near Bajada del Agrio, Rio Agrio [­38.383, ­70.033], 600 m, 16.XII.1966, MEI, EIS, 1♂ MEI 074531, 1♀ 110487 ( MEIC) , riverbottom dunes. SANTA CRUZ. 5 km W Comandante Luis Piedra Buena [­49.965, ­68.949], 130 m, 25.XI.1966, EIS, MEI, 8♂ ME I 074519–22 ( MEIC) , 074523 (MEUC), 074524 (CAS), 074525 (CNC), 074526 (USNM), 1♀ 110486 ( USNM) ; 2.4 km S Fitz Roy [­47.055, ­67.25], 210 m, 12.XII.1966, MEI, EIS, 2♂ MEI 073594–5, 2♀ 073592–3 ( INHS) ; 5 km NW Piedra Buena [­49.933, ­68.936], 130 m, 19.XII.1966, EIS, MEI, 3♀ MEI 074516 ( CNC) 074517 (CAS) 074518 (MEUC), low dunes; Puerto Coyle [­50.95, ­69.2], 10 m, 26.XI.1966, MEI, EIS, 5♀ MEI 07356–9 (ME IC), 074508 ( BMNH) ; 40 km SW Puerto Coyle [­51.204, ­69.454], 25.XI.1966, L. E. Peña, 3♂ MEI 074507, 074509, 074513, 2♀ 074510–11 ( MEIC) .