Microthereva variventris Malloch

Webb, Donald W., 2006, The neotropical genera Microthereva Malloch and Peralia Malloch (Diptera: Therevidae: Therevinae), Zootaxa 1295, pp. 1-27 : 10-13

Microthereva variventris Malloch

( Figs. 11–19 , 30 )

variventris Malloch (1932: 245 sp. key, 246 male /fem. desc.). Type locality Argentina, Río Negro, Bariloche. Holotype male in BMNH.

Diagnosis

Microthereva variventris is separated from M. argentiventris by the characters in the key as well as the posterolateral margin of the male epandrium being pointed ( Fig. 11 ); the cerci extending distal to the hypoproct ( Fig. 11 ); setae continuous across the posterior margin of male sternite 8 ( Fig. 12 ); gonocoxite in lateral view oval ( Fig. 14 ); anterior margin of dorsal apodeme deeply emarginate anteriorly ( Fig. 16 ); ventral apodeme extending medially beyond anterior margin of dorsal apodeme ( Fig. 17 ); distiphallus in lateral view curved ventrally ( Fig. 18 ), lacking subapical hood; posterior half of ejaculatory apodeme triangular ( Fig. 16 ); female abdomen dark reddish brown, glossy, pruinescence white, dense laterally on tergites 1–7.

Redescription of male

Variation (n=5)

Body length 5.3–7.7, 6.0 mm.

Head. Length 0.78–0.96, 0.88 mm. Frons dark brown, pruinescence brownish gray; setae dark brown. Antenna dark brown, pruinescence gray, dense on scape and pedicel; antenna/head length 0.72–0.93, 0.82; scape length 0.24–0.32, 0.28 mm, width 0.12–0.18, 0.15 mm, length/width 1.3–2.7, 1.9, scape/pedicel length 2.4–4.0, 3.2, scape/flagellum width 0.67–1.29, 0.99, setae dark brown, elongate, macrosetae dark reddish brown; pedicel length 0.08–0.12, 0.09 mm, width 0.12–0.16, 0.14 mm, length/width 0.56–0.62, 0.58, setae dark brown, elongate; flagellum length 0.32–0.38, 0.34 mm, width 0.14–0.18, 0.16 mm, length/width 1.9–2.4, 2.2, flagellum/scape width 1.1–1.3, 1.2. Parafacial pruinescence whitish gray; setae dark brown. Maxillary palpus dark yellowish brown, apex dark brown; length 0.36–0.44, 0.40 mm, width 0.08 mm, length/width 4.5–5.5, 5.0; setae white. Genal setae white. Occipital setae white, elongate, becoming dark brown dorsally; macrosetae absent. Postocular macrosetae absent.

Thorax. Macrosetae 3 np, 2 sa, 1 pa, 1–2 dc, 2 sc. Mesonotum dark brown, pruinescence whitish gray, dense; vittae pale brown; setae dark brown, elongate, erect. Postpronotal setae dark brown. Pleuron dark brown, pruinescence gray; setae white, elongate on propleuron, anepisternum, katepisternum, dark brown on laterotergite, scutellum and dorsal half of anepisternum; pale yellow on metanepisternum. Wing. Membrane opaque, brown; veins dark brown; length 4.7–6.0, 5.1 mm, width 1.3–1.8, 1.5 mm length/width 3.2–4.3, 3.3. Halter knob pale yellow. Legs. Coxae with apical macrosetae dark reddish brown on fore­ and midcoxa, apical macrosetae and posterolateral macroseta absent on hindcoxa. Femora dark brown, pruinescence white; ventral setae white; av 0:0:1–2, pv 0:0:0–1. Tibiae dark brown. Tarsi dark brown.

Abdomen. Dark reddish brown, pruinescence white on tergite 1, dense posterolaterally on tergites 2–6 in dorsal view; dorsal setae pale yellow on tergite 1, dark brown on remaining tergites, intermixed with scattered pale yellow setae; lateral setae pale yellow on tergites 1–3, dark brown on remaining tergites. Terminalia (MEI 147507). Dark brown. Tergite 8 ( Fig. 11 ), posterior margin broadly emarginate; setae dark brown; median length thick (0.22 mm). Sternite 8 ( Fig. 12 ) with anterior and posterior margins truncate, sides rounded; setae dark brown continuous across posterior margin. Epandrium ( Fig. 11 ), posterolateral margin pointed; setae dark brown. Cercus ( Fig. 11 ), ending distal to apex of hypoproct. Hypoproct ( Fig. 11 ), ending basal to apex of cercus. Gonocoxite ventral view ( Fig. 12 ), sides rounded, posterolateral margin broadly rounded, setae dark brown on posterior third; lateral view ( Fig. 14 ) broad, oval; inner gonocoxal process ( Figs. 12–14 ) dark yellow with setae dark yellow along lateral margin. Gonostylus dark yellow ( Fig. 15 ) broad, sinuate with two apical points, setae dark yellow. Aedeagus with dorsal apodeme ( Fig. 16 ) relatively narrow, tapered posteriorly, anterior margin deeply emarginate; ventral apodeme ( Fig. 17 ) T­shaped, diverging anteriorly, extending medially beyond anterior margin of dorsal apodeme, anterior margin truncate; distiphallus dorsal view ( Fig. 16 ) tapered posteriorly, apicolateral spines absent, lateral view ( Fig. 18 ) short, thick, curved ventrally at 90° angle, lacking subapical hood; ejaculatory apodeme ( Fig. 16 ), posterior half triangular, anterior half narrow, slightly expanded anteriorly.

Female

Similar to male except for following.

Variation (n=4)

Body length 6.5–7.3, 6.9 mm.

Head. Length 0.82–0.84, 0.84 mm. Frons broad, pruinescence brownish gray, dense; setae dark brown, elongate. Antenna/head length 0.81–0.88, 0.87; scape length 0.24–0.32, 0.27 mm, width 0.12–0.14, 0.14 mm, length/width 1.7–2.3, 2.0, scape/pedicel length 3.0–4.0, 3.3, scape/flagellum width 0.92–1.00, 0.97; pedicel length 0.08 mm, width 0.12–0.14, 0.13 mm, length/width 0.6–0.7, 0.6; flagellum length 0.36–0.38, 0.37 mm, width 0.13–0.14, 0.14 mm, length/width 2.7–2.8, 2.7, flagellum/scape width 1.2–1.5, 1.4. Maxillary palpus dark reddish brown; length 0.30–0.36, 0.34 mm, width 0.08 mm, length/ width 3.8–4.5, 4.2.

Thorax. Macrosetae 2–3 np, 1–2 sa, 1 pa, 0–2 dc, 2 sc. Setae not distinguishable on metanepisternum. Wing. Length 5.0–5.5, 5.3 mm, width 1.7–1.9, 1.8 mm, length/width 2.6–3.2, 3.0. Legs. Anteroventral macrosetae 0:0:1–2, pv 0:0:0–1.

Abdomen. Dark reddish brown, glossy, pruinescence gray, dense on posterolateral area of tergites 2–6; dorsal and lateral setae dark brown. Terminalia (MEI 112416). Furca and spermathecal complex ( Fig. 19 ), furcal length 0.60 mm, width 30 mm.

Distribution

Microthereva variventris is distributed in western Argentina ( Fig. 30 ).

Habitats and phenology

Microthereva variventris has been collected in November.

Specimens examined

Type specimen. The holotype male of Microthereva variventris Malloch is labeled "Bariloche, 5.xi.1926, Argentina Terr. Rio Negro, F. & M. Edwards" and is in the BMNH (Type No. BMNH (E) 241999). Other specimens. ARGENTINA. RIO NEGRO. Bariloche [­41.15, ­71.3], –. XI.1926, Shannon, R. & E., 5♂ MEI 112413, 112415, 112417, 147508 ( USNM), 147507 ( INHS),, 4Ψ 112411 –2, 112414, 112416 ( USNM).

Figures

FIGURES 11 – 19. Microthereva variventris. 11. Tergite 8, epandrium, cerci, hypoproct, dorsal view. 12. Sternite 8, gonocoxite, ventral view. 13. Gonocoxite, dorsal view. 14. Gonocoxite, lateral view. 15. Gonostylus, lateral view. 16. Aedeagus, dorsal view. 17. Aedeagus, ventral view. 18. Aedeagus, lateral view. 19. Female internal reproductive organs. Scale = 0.1 mm.

FIGURES 30 – 32. Distribution maps. 30. Microthereva argentiventris (closed circles), M. variventris (arrow). 31. Peralia hermanni. 32. Peralia vittata.