Mesembrinella randa (Walker, 1849)

(Figs 85–86, 175–176, 230, 273, 317, 361, 402, 446, 479, 488)

Dexia randa Walker, 1849: 852 . Lectotype female (NHMUK), here designated. Type locality: Brazil.

Eumesembrinella randa: Peris & Mariluis (1984: 263); Toma & Carvalho (1995: 142); Kosmann et al. (2013: 77); Wolff & Kosmann (2016: 866); Marinho et al. (2017: tab. 1); Velásquez et al. (2017: 108).

Mesembrinella randa: Cerretti et al. (2017: tab. 2).

Diagnosis. A large fly averaging 12 mm (11–13/5) in length. Postpronotal setae 2x 2; base of wing mostly hyaline; anterior margin of wing infuscated from costa to vein R 2+3; T3–4 concolorous, without distinct posterior bands; posterior edge of T4 lacking marginal setae dorsally; posthumeral seta present, often reduced; rim of upper calypter dark.

Redescription. Male. Head. Frons broad, 0.078 (0.07–0.09/5) of head width at narrowest, slightly narrower than width of parafacial at level of lunule; fronto-orbital, parafacial, gena and antenna pale golden, frontal vitta darker orange; frontal setae ascending about 60% of distance to vertex; frontal vitta obliterated midway, gena with typical horizontal row of stout setae midway, otherwise with scattered weak tan setae; posterior margin with few golden setae; postgena orange with pale tomentum and golden setae; occiput dark orange with silvery tomentum and golden setae; median occipital sclerite shiny dark brown; antenna pale gold except brown setae on arista; palpus typical; ocellar triangle medium-sized, anterior ocellus about 2x size of posterior ocelli; supravibrissal setae short and brown, in short row, ascending about 1/10 of distance to antennal base.

Thorax. Dorsum dark orange midway, with 4 broad golden tomentose stripes, lateral presutural areas pale orange; pleural area orange; chaetotaxy: ac 0:1, dc 2:3, ia 0, ph 1, often somewhat reduced, ppn 2x 2, kat 1:1, meral setae typical, 1 pair of ac parallel or slightly converging, sa and lat absent, bas typical, 1 weak pb, 1 disc; subscutellum moderately developed; spiracles orange, medium-sized; legs: femora orange, tibiae and tarsi tan to brown. Wing with anterior edge infuscated from costa to R 2+3; subcostal sclerite orange and bare; basicosta and tegula orange; section IV 0.30 of section III; discs of upper and lower calypters reddish; rim of upper calypter dark with long pale setae, rim of lower calypter pale with long reddish setae.

Abdomen. Dorsum of T1+2–3 orange, T4–5 shiny blue; T3–4 with dorsolateral pair of marginal setae; rear margin of T4 without marginal setae; disc of T5 with dense, short, fine setae only. Terminalia in lateral view: surstylus with moderate backward curve [sharper than in M. quadrilineata], cercus with apical hook (Fig. 85); in posterior view, cerci broad at base, then tapering gradually to tip (Fig. 86); phallus in lateral view with epiphallus of moderate length and with slight backward curve (Fig. 175); in dorsal view, hypophallus rounded with fine serrations, as in Fig. 176; T 6, STS7+8, pre- and postgonite, ejaculatory sclerite, ST6 and hypandrium as in Fig. 230; ST1–5 very narrow, as in Fig. 273.

Female. Similar to male except frons 0.278 (0.25–0.30/5) of head width at narrowest. T6 of FU shape; T7 continuous, darkened midway, pale laterally; T8 as separate sclerites; epiproct divided midway (Fig. 317); ST6–8 and hypoproct as in Fig. 361; spermathecae filiform (Fig. 402); ST1–5 as in Fig. 446.

Type material examined. LECTOTYPE ♀ (Brazil; NHMUK; Fig. 479), here designated, labeled: Brazil. / Pres. by the / Entomological / Club / 44.12; LECTOTYPE ♀ / Dexia / randa / Walker, 1849 / Designated by / Dear and Pont. [red border]; SYNTYPE ♀ / Dexia / randa Walker / 1849, List Dipt. / Brit. Mus., 4: 852 [red border]; LECTO-/ TYPE [round label with purple border]; Dexia / Type / randa / Walk. [round label with green border]; Ent. Club. / 44-12.

Remarks. Dexia randa was described based on at least two specimens from Brazil (Walker 1849: 853), but only one of these type specimens is currently housed in NHMUK (N. Wyatt, pers. comm.). Dear and Pont selected and labeled this specimen as a lectotype for this species, without publishing the designation. The same specimen is here formally designated as the lectotype of this nominal species. The lectotype has a frons to head width of 0.30 at narrowest, 1 small ph and no presutural ia. It is significantly damaged, with 5 legs missing (only left mid leg attached) and the left wing broken off, kept in a vial pinned below the specimen; the macula on the wing is faint and faded.

Additional material examined. Bolivia, Tumupasa. 1 ♀, Mulford Biol. Expl 1921–1922. Xii, W.M. Mann (LACM) . Brazil, Rondônia. 1 ♂*, 4 ♀♀ ♦ (TLW281 – TLW284), 19 ♀♀, 62 km SW Ariquemes, nr Fzda. Rancho Grande, 4–16.xi.1997, Fish Carrion Pitfall, J.E. Eger (FSCA) ; 1 ♀, same data except 6–15.xii.1990, D.A. Rider & J.E. Eger (FSCA); 1 ♀, same data except 17–24.iii. 1989, 180 m, W.J. Hanson (LACM) . Colombia, Caqueta. 1 ♂*, 1 ♂, Rio Orteguaza, nr. Rio Peneya, 14–18.i.1969, Duckworth & Dietz (LACM) . Peru, Cusco. 1 ♂, 1 ♀, Pilocapata, Villa Carmen, 12°53ʹS 71°24ʹW, v.2014, Multilure trap, M. Choque (FSCA) . Lorenzo. 1 ♂*, 2 ♂♂, Boqueron, 30.vi.1965, J. Schunke (LACM) ; 1 ♀, same data except 9.vii.1965 (LACM); 1 ♀, same data except 4.vii.1965 (LACM); 1 ♀, same data except 500 m, 14.vii.1965 (LACM); 1 ♀, same data except 22.iii.1964 (LACM); 2 ♀♀, 160 km NE Iquitos, Explornapo Camp, 2 km from Rio Napo on Rio Sucusari, 27–31.viii.1992, human dung trap, J. Castner & Skelley (FSCA) . Pasco. 2 ♂♂, 1 ♀ *, 3 km N. Puerto Bermudes, 200 m, jungle, 27.vi.1980, fish bait, D. Baumgartner, B. Greenberg (BG); 1 ♀, no other data (CEUA) .

Distribution. Bolivia, Brazil, Colombia, Peru. Guimar„es (1977) listed it from Guyana, Marinho et al. (2017) also listed it from French Guiana and Venezuela.

Remarks. Four specimens (TLW 281–284) were barcoded and formed a distinct group close to M. benoisti (Fig. 488).