Stenogephyra, Lyneborg, 1987

Lyneborg, Leif, 1987, Notes on the Phycini of southern Africa with the description of a new genus and two new species (Diptera: Therevidae: Phycinae), ANNALS OF THE NATAL MUSEUM 28 (2), pp. 467-474 : 470-472

Genus Stenogephyra gen. n.

Etymology: stenos = narrow; gephyra = bridge.

Gender: feminine. Type species: Stenogephyra torrida sp. n., present designation. Diagnosis

Small, blackish, slender-bodied species. Eyes widely separated in both sexes, frons about 3 times as wide as ocellar tubercle and polished black ( Fig. 7 ). Face strongly protruding, forming a polished black convex callus below antennae. Gena wide. Scape very short; first flagellomere 4-5 times as long as scape, longest in O. Flagellar style very minute, obviously one-segmented, the usual apical spine (cf. Figs 8-9 ) not discernible. Palpus two-segmented, apical segment longer than basal segment. Proboscis short.

Thoracic chaetation: 2-3 np, 1 sa, 1 pa, 0-1 dc, 1 sc. Mesonotal pile black and uniform. Prosternum bare. Pleura practically without any pile. Ambient vein terminating at vein MI' Vein M2 usually abbreviated and not reaching wing-margin. Cell m3 petiolate. Cell r4 very slender, 4-6 times as long as wide at apex, veins R4 and Rs being nearly straight. Proximal end of discal cell pointed or closed by a very short, transverse cross-vein. Wings unpatterned. Mid coxa without pile on posterior surface. All femora without setae. Tibiae short, with few and short setae. Setae of mid and hind tarsi very short.

Abdomen short and wide, nearly cylindrical, in 0 suddenly tapering from segment 5 onwards, in <i' more gradually tapering. Dorsum shiny black with a short pile.

♂ terminalia ( Figs 10-18 ). T8 ( Fig. 18 ) and S8 ( Fig. 17 ) of a simple rectangular shape. Also epandrium ( Fig. 11 ) simple, without lateral projections. Ventral epandrial sclerite ( Fig. 12 ) as in Phycus , large, free, nearly as long as epandrium; not attached to aedeagus. Cerci wedge-shaped, short. Gonocoxites ( Fig. 13 ) separated ventrally; no remnant of a hypandrium. Each gonocoxite with a narrow sclerotised bridge on inside (as in some Xestomyzini, see Lyneborg 1972), proximally to the insertion of the gonostylus. Dorsal apodeme of aedeagus connected to dorsal edge of gonocoxites via a sclerotised bridge. Distiphallus a short, rather wide, apically sharply pointed, tube ( Fig. 16 ). Ventral apodeme very short and spoon-shaped. Ejaculatory apodeme with enlarged distal portion.

♀ terminalia ( Figs 19-21 ). T8 ( Fig. 21 ) large and squarish, its posterior margin not distinctly demarcated. T9 absent. TIO strongly constricted in mid-line, with 8-9 setae on each side. Cerci wedge-shaped as in 0'. S8 ( Fig. 19 ) broadly spindleshaped and uniformly pilose, posteriorly with a deep slit which continues into an infolded penial guide. Vaginal apodeme ( Fig. 20 ) broadly ring-shaped anteriorly, while posterior portion is open and horseshoe-shaped. S9 absent. Subgenital plate squarish with a low incision into posterior margin.

Distribution

The genus will probably prove to be restricted in distribution to the western Cape Province and Namibia.

Relationship

Phycus and Stenogephyra form a monophyletic group. They share the following synapomorphic characters: (a) first flagellomere elongate; (b) femora without setae; (c) hypandrium vestigial or absent. A number of symplesiomorphic character states should also be mentioned. These are: (a) male eyes broadly separated; (b) palpus two-segmented; (c) prosternum bare; (d) ventral epandrial sclerite large. Autapomorphic characters for Stenogephyra are as follows: (a) face protruding; (b) flagellar style one-segmented and obviously without apical spine; (c) ambient vein terminating at M1.

Key to species of Stenogephyra

1. Vein M2 usually abbreviated; its apex separated from wing-margin by a distance equal to width of discal cell ( Fig. 6 ). Three pairs of notopleural setae. One pair of dorsocentral setae....................... ... ... torrida sp. n.

Vein M2 usually complete to wing-margin. Two pairs of notopleural setae. Dorsocentral setae not distinct from the usual mesonotal pile .. minuta sp. n.

Figures

Figs 6-22. Stenogephyra gen. n. 6-21. S. torrida sp. n. 6. 7. Male head in frontal view. B. Male antenna. 9. Female antenna. 1O-1B. Male terminaha. 10. Male genitalia in lateral view. 11. Epandrium and cerci in dorsal view. 12. Epandrium, cerci and ventral epandrial sclerite in ventral view. 13. Gonocoxites with gonostyli in ventral view. 14. Left gonocoxite with ~onostylus and aedeagal complex in dorsal view. 15. Right gonocoxite with gonostylus in mterior view. 16. Aedeagus in lateral view. 17. Sternite B. lB. Tergite B. 19-21. Female terminalia. 19. Sternite B. 20. Subgenital plate and vaginal apodeme. 21. Tergite B, tergite 10 and cerci in dorsal view. 22. S. minuta sp. n., male antenna. Scale: 1 mm for 6 and 7,0,5 mm for the rest.