Brachygasterina major Malloch, 1934

De Carvalho, C. J. B. & Pont, A. C., 2006, Taxonomy, cladistics and biogeography of the South American genus Brachygasterina Macquart (Diptera: Muscidae), Zootaxa 1151, pp. 1-26 : 10-11

Brachygasterina major Malloch, 1934 ( Figs 2 , 7, 11 , 13 )

Brachygasterina major Malloch, 1934: 339 .

Diagnosis

This is the only species of Brachygasterina that can be identified by a wing character, as base of R4+5 has setulae on both surfaces; prealar absent in males but very short in females.

Redescription

Head: Frons of male narrow, at narrowest point hardly wider than diameter of anterior ocellus ( Fig. 13 ); frons of female broad, at narrowest point 0.37–0.41 of head width ( Fig. 2 ). Eye with a few scattered short hairs ( Figs 7, 11 ). Fronto­orbital plate of male white pruinose, of female white pruinose on lower 1/3 and matt black on upper 2/3; parafacial and gena whitish, parafacial with a small (male) or large (female) matt patch at level of antennal insertion; occiput grey dusted. Male with numerous fine frontal setae and setulae, reaching from lunula to anterior ocellus; female with 12–13 pairs of frontal setae and 2 pairs of weak reclinate orbitals. Facial ridge with setulae not reaching even to mid­level of first flagellomere ( Figs 7, 11 ). Parafacial and gena broad, in lateral view the former 0.5 (male) or 0.7 (female) of first flagellomere width. Proboscis thinly dusted. Palpus black.

Thorax. Ground­colour subshining dark metallic violet­blue, dusted light grey as in violaceiventris in posterior view. 2–3+3–4 developed acrostichals; 2 strong posterior intraalars; prealar absent in male, strong and subequal to second notopleural seta in female; notopleuron with a few setulae around base of each seta. Scutellum greyish dusted, laterally setulose; with strong apical, basal and lateral setae, and several stronger setae on disc. Prothoracic spiracle dark brown. One strong proepisternal seta and several setulae; 1 strong proepimeral seta and numerous long setulae. Katepisternals 1+1–2. Katatergite long pilose.

Legs. Dark brown. Fore tibia without posterior seta, without (male) or with 2–3 short (female) anterodorsal setae. Mid femur in male with rather long, dense, fine anteroventral and posteroventral setae along most of its length; 1 short anterior and 3–4 posterior preapical setae. Mid tibia with 4–5 posterior setae, without anterodorsal or ventrals. Hind femur with a row of strong anteroventral setae, and with strong posteroventrals in basal half; 5–6 anterodorsal and 4–5 anteroventral setae; dorsal preapical strong, anterodorsal preapical weak, without posteroventral apical.

Wing. Weakly smoky, veins dark brown. Node at base of vein R4+5 with setulae dorsally and ventrally, otherwise veins bare except costa. Crossvein dm­cu very sinuous.

Vein M running straight to wing­margin. Calypters dark brown, lower one slightly longer than upper one. Knob of haltere dark brown.

Abdomen. Subshining metallic blue­violet, dulled by grey to light grey dust when viewed from behind. Sternite 1 setulose.

Measurements (n=4): Body length, 8.5–10 mm. Wing length, 9.5–11.5 mm.

Type material examined

Holotype, male, ARGENTINA: Rio Negro, Bariloche, xi.1926 (R.& E. Shannon) ( BMNH).

Paratypes, 15 males and females, ARGENTINA, CHILE ( BMNH).

Other material examined. CHILE. Nuble: Termas (Tolhuaca), 20.i.1950 (L.E. Peña), 3 females ( MZSP); Lago Galletue (Cord. Lonquimay), i.1962 (L.E. Pena), 1 male ( MZSP). Remarks. Holotype in fair condition: right fore leg, left fore tibia and tarsi, middle right leg and left tibia and tarsi are missing. Paratypes in fair condition, 1 male without head. This species was also well described by Malloch (1934) and Carvalho (1989b), and was keyed by Carvalho and Couri (2002a). It was attracted to cooked meat (F.W. Edwards in Malloch, 1934).

Geographic distribution

Chile, Argentina.

Figures

FIGURES 1 – 5. Female head, frontal view. 1. Brachygasterina andina. 2. B. major. 3. B. stuebeli. 4. B. valdiviensis. 5. B. violaceiventris. Scale bar: 1 mm.

FIGURES 6 – 12. Head, lateral view. 6. Female, Brachygasterina andina. 7. Female, B. major. 8. Female, B. stuebeli. 9. Female, B. valdiviensis. 10. Female, B. violaceiventris. 11. Male, B. major. 12. Male, B. violaceiventris. Scale bar: 1 mm.

FIGURES 13 – 14. Male head, frontal view. 13. Brachygasterina major. 14. B. violaceiventris. Scale bar: 1 mm.