Brachylinga fraterna (Kröber)

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 : 79-81

Brachylinga fraterna (Kröber)

( Figs. 13, 36, 59, 82, 105, 128, 151, 174)

fraterna Kröber (1911: 499 male key, 521 orig. desc.; 1913:30 dist.; 1928a:6 dist., 9 male key) ( Psilocephala ); Irwin and Webb (1992:87 checklist, comb. change) ( Brachylinga ). Type locality Brazil, Soledade. Holotype male in NMW.

Diagnosis

Brachylinga fraterna is taxonomically associated with B. curacaoensis in lacking setae on the katepisternum; in having the postocular, mesonotal, and coxal macrosetae dark reddish brown; in having the male parafacial silver or gray over the entire surface; the male frons lacking setae; in having the wing cell m 3 closed; the maxillary palpus pale yellow or at most with the basal half reddish brown; the male tergite 8 ( Fig. 13) narrow medially; and in having the posterior margin of the hypoproct emarginate ( Fig. 13). Brachylinga fraterna differs from B. curacaoensis in having the gonocoxite in ventral view ( Fig. 36) with the medial margin rounded anteriorly then deeply emarginate before expanding into a broad posterior projection, which then tapers apically to a blunt point; in dorsal view ( Fig. 59) the gonocoxite lacks a posteromedial lobe; in lateral view ( Fig. 82) the gonocoxite is square, the sides irregular and the posterior margin truncate; the distiphallus in dorsal view ( Fig. 128) thick, expanded apically and in lateral view ( Fig. 174) the apical third of the distiphallus is bent ventrally at a 90° angle.

Redescription of holotype male (MEI 147292)

Body length 5.9 mm.

Head. Length 0.84 mm. Ommatidia smaller ventrally and laterally. Frons pruinescence white, pale brown dorsally; setae absent. Antenna/head length 0.65; dark yellow, second and third flagellomeres dark brown; scape length 0.16 mm, width 0.11 mm, length/width 1.5, scape/pedicel length 2.3, scape/flagellum width 0.73, setae dark reddish brown, short; pedicel length 0.07 mm, length/width 0.64; flagellum length 0.32 mm, width 0.15 mm, length/width 2.1, flagellum/scape length 2.0. Parafacial pruinescence white. Maxillary palpus yellow; length 0.42 mm, length/width 7.0; setae pale yellow. Genal setae white. Occipital setae white becoming lanceolate dorsally; macrosetae absent. Postocular macrosetae dark reddish brown.

Thorax. Macrosetae dark reddish brown, 3 np, 2 sa, 1 pa, 1 dc, 2 sc. Mesonotum pruinescence white, dense; setae dark brown, short 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 hyaline, veins pale yellow; length 4.7 mm, length/ width 2.8; pterostigma indistinct; cell m 3 closed, petiolate. Halter pale yellow. Legs. Coxa setae white, present on posterior half of midcoxa; macrosetae dark reddish brown. Fore­ and midfemur pale reddish brown, hindfemur dark yellow; ventral setae white, elongate on fore­ and midfemora; av 1:0:4, pv 0:0:4. Tibiae yellow (tibiae missing on hindlegs). Tarsomeres 1–2 yellow; 3–5 pale brown (tarsi missing on hindlegs).

Abdomen. Pale reddish brown, pruinescence white; dorsal setae white, appressed; lateral setae white. Terminalia (MEI 045965) reddish brown. Tergite 8 ( Fig. 13), narrow medially (0.02 mm); setae dark yellow, absent medially on posterior margin. Sternite 8 ( Fig. 36) quadrate, posterior margin emarginate. Epandrium ( Fig. 13), sides tapered apically, posterior margin truncate; setae dark yellow. Cercus ( Fig. 13) ending basal to apex of hypoproct. Hypoproct ( Fig. 13), posterior margin emarginate, ending distal to apex of cercus. Gonocoxite ventral view ( Fig. 36), medial margin rounded anteriorly becoming deeply emarginate before expanding into broad posterior projection, then tapering apically to short, blunt point; setae dark yellow; dorsal view ( Fig. 59), posteromedial lobe rounded, gonocoxal bridge absent; lateral view ( Fig. 82) square, sides irregular, truncate apically; ventral lobe ( Fig. 36) with ventral spines. Gonostylus ( Fig. 105), basodorsal lobe moderately large, curved anteriorly; ventral margin curved, setae dark yellow, not directed apically in distinct tuft; fine, short spines absent laterally. Aedeagus with dorsal apodeme ( Fig. 128) oval, posterolateral margin rounded; ventral apodeme ( Fig. 151) tapered anteriorly, not extending to anterior margin of dorsal apodeme; distiphallus dorsal view ( Fig. 128) thick, expanded apically, lateral view ( Fig. 174), apical third bent ventrally at 90° angle, apicolateral spines small; ejaculatory apodeme ( Fig. 128), anterior margin bifurcate.

Variation (n=2). Body length 5.9 mm.

Thorax. Macrosetae 3 np, 2 sa, 1 pa, 1 dc, 2 sc. Legs. Anteroventral macrosetae 1:0:4–7, pv 0:0:4–5.

Female Unknown.

Distribution Brachylinga fraterna is known from two males collected in Brazil.

Habitats and phenology Brachylinga fraterna has been collected in April and December.

Specimens examined

Type specimen. The holotype male of Psilocephala fraterna Kröber (MEI 147292) is labeled "20.4, Solidade, Bras. Exped, Penther. ’03" and is in the NMW. Other specimens. BRAZIL. CEARA. Fortaleza , 6.XII.1960, N. Marston, 1♂ MEI 045965 ( KSUC) .