Brachygasterina violaceiventris Macquart, 1851

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 : 14-16

Brachygasterina violaceiventris Macquart, 1851 ( Figs 5 , 10, 12 , 14 )

Brachygasterina violaceiventris Macquart, 1851: 232 . Diagnosis

This species is closely related to B. valdiviensis but can be distinguished by the absence of a dorsal preapical seta on fore tibia and by the other characters given in the key. In the female terminalia, sternite 6 is divided in two parts, the distance between these two parts being less in B. violaceiventris than in B. valdiviensis ( Soares & Carvalho 2004) .

Redescription

Head: Frons of male narrow, at narrowest point equal to twice diameter of anterior ocellus ( Fig. 14 ); frons of female broad, at narrowest point 0.33–0.37 of head width ( Fig. 5 ). Eye with sparse but distinct hairs ( Figs 10, 12 ). Fronto­orbital plate of male dull grey, subshining in upper half, of female matt, blackish; parafacial, face and gena dull grey (male) or brownish­grey (female) pruinose, parafacial with a large, conspicuous, matt patch at level of antennal insertion; occiput metallic blue to violet. Male with numerous fine frontal setae and setulae, reaching from lunula to anterior ocellus; female with 7 pairs of frontal setae and 2 weak reclinate orbital setae. Facial ridge with setulae hardly reaching to mid­level of first flagellomere. Parafacial narrow, hardly 1/3 width of first flagellomere; gena broad. Proboscis thinly dusted. Palpus black.

Thorax. Ground­colour subshining dark metallic violet­blue, with 3 broad grey to brownish­grey vittae, merging into a dusted area behind suture; with an additional pair of vittae through posterior intra­alar setae, a patch over humeral, notopleural and humeral area, and a transverse line along suture. 3+4 developed acrostichals; 2 strong posterior intra­alars; prealar strong, longer than anterior notopleural seta; notopleuron with 1–2 setulae next to each seta. Scutellum coloured as mesonotum, dulled by thin dust; laterally setulose; with strong apical, basal and lateral setae, and several stronger setulae on disc. Prothoracic spiracle dark brown. One strong proepisternal seta and several setulae; 1 strong proepimeral seta and numerous long setulae. Katepisternals (1–)2+3. Katatergite long pilose.

Legs. Dark brown. Fore tibia without posterior or anterodorsal setae. Mid femur in male with rather dense fine anteroventral and posteroventral setae on over basal half, in female the posteroventrals not as long as femoral depth and the anteroventrals shorter, sparser; 1 short anterior and 3 posterior preapical setae. Mid tibia with 3 posterior setae, without anterodorsal or ventrals. Hind femur with complete rows of strong anteroventral and posteroventral setae, shorter and sparser in female than in male; 2 anterodorsal and 3 anteroventral setae; dorsal preapical strong, anterodorsal preapical weak, without posteroventral apical.

Wing. Clear, smoky at base, veins dark brown. 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, hardly dusted. Sternite 1 bare.

Measurements (n=4): Body length, 7.5–8.6 mm. Wing length, 6.5–9.5 mm. Type material examined

Lectotype male and paralectotypes 3 females in MNHN (see Séguy 1938), here designated and labelled accordingly. These four specimens have the accessions number 15.43, which refers to material from Chile, with no further locality data, collected by Gay.

Other material examined. CHILE. Concepción (Hualpen Parque Botânico), ii.1970 (T. Cekalovic), 1 male (MZSP); Nuble: Termas (Tolhuaca), 20.i.1950 (L.E. Peña), 1 female (MZSP). ARGENTINA. Rio Negro: Bariloche, xi.1926 (R. & E. Shannon), 1 male, 1 female (MZSP).

Remarks

This species was also well described by Malloch (1934) and Carvalho (1989b), and was keyed by Carvalho and Couri (2002a). According to information on the labels, the species was reared from a decomposing honey bee colony.

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.