Acatopygia Kröber

Winterton, Shaun L., 2007, Revision of the Australian stiletto fly genus Acatopygia Kröber (Diptera: Therevidae: Agapophytinae), Zootaxa 1405, pp. 51-62 : 52-53

Acatopygia Kröber

( Figures 1–4 )

Acatopygia Kröber, 1912a: 149 . Type species: Acatopygia pulchella Kröber, 1912a: 149 (by monotypy). – Kröber, 1913: 17 (redescription); Mann 1928: 42 (redescription); Irwin & Lyneborg, 1989: 353 (catalogue); Winterton et al. 2001: 195 (diagnosis).

Spatulipalpa Kröber, 1912b: 221 . Type species: Spatulipalpa paradoxa Kröber, 1912b: 221 (by subsequent designation, Irwin & Lyneborg 1989: 353). – Kröber, 1913: 19 (redescription); Irwin & Lyneborg 1989: 353 (synonymy).

Diagnosis

Body slender, elongate; frons flat or slightly bulbous around base of antenna, often covered with elongate setae; wing strongly banded; wing cell m3 closed; relatively elongate hind legs; epandrium arched, lateral margins extending ventrally; medial atrium present posteriorly between gonocoxites; gonocoxal apodemes approximately equal to length of gonocoxite; hypandrium with patch of strong, posteriorly directed setae; three spermathecae; spermathecal sac small rounded.

Redescription

Male and female. Body length: 6.0–8.0 mm.

Head. Shape longer than high; frons flat, slightly raised around base of antennae, overlain with pubescence but sometimes with glossy patch above antennae, usually admixed with elongate setae, male frons width at narrowest point either narrower than or equal width to ocellar tubercle, female frons much wider than ocellar tubercle; lower frons and face with silver or grey pubescence; ocellar tubercle black, overlain with grey pubescence admixed with long, dark setae; male occiput concave or slightly convex; usually single row of postocular setae in male (2–3 poorly defined rows in male of A. olivacea sp. nov.); female occiput convex; 2–3 poorly defined rows of postocular setae; antennae positioned low on frons; length equal to or slightly shorter than head length; setae on antennae often enlarged; scape slightly wider than pedicel; flagellum gradually tapered ( A. olivacea sp. nov.) to turbinate ( A. pulchella ), length approximately equal to combined length of scape and pedicel.

Thorax. Scutum dark, overlain with brown, green or grey pubescence, admixed with scattered dark setae, setae longer in male; macrosetae dark; scutellum relatively small, dark, sometimes overlain with matte, black pubescence anteriorly; pleuron glossy dark brown or black, partially overlain with dense, grey pubescence and long pale setae; coxae and legs dark or variously patterned with yellow; fore and hind femora with elongate velutum patch on ventral and posteroventral surfaces respectively; hind femur much longer than other femora; anteroventral subapical seta on hind femur absent (a row of dark, ventral setae present on all femora in A. pulchella ); wing hyaline with dark banding, third medial cell (m3) closed; scutal chaetotaxy: notopleural (np), 2– 4; supraalar (sa), 1; postalar (pa), 1–2; dorsocentral (dc), 3–6; scutellar (sc), 1.

Abdomen. Elongate, glossy black or dark brown, extensive velutum dorsally on male abdomen (absent in A. olivacea sp. nov.); setae on abdomen of uniform size and distribution, not concentrated posteromedially on tergite 2.

Male genitalia. Epandrium width equal to length medially, posterolateral corners rounded or pointed, sometimes extending anterolaterally and ventrally to partially conceal gonocoxites; cercus elongate or short; tergite 8 emarginate medially; gonocoxite with large medial atrium with velutum­covered membrane; hypandrium large, quadrangular to sub­triangular, partially fused to gonocoxites laterally, numerous dark setae located medially along posterior margin; ventral lobe elongate, extending medially and dorsally, velutum present apically; gonocoxal apodeme narrow, shorter than or equal to gonocoxite length; gonocoxal process present, narrow, shorter than or equal in length to inner gonocoxal process; inner gonocoxal process spatulate apically; gonostylus curved medially along length; distiphallus straight or curved; dorsal apodeme of parameral sheath present, ‘T’­shaped, fused laterally to gonocoxal apodeme in A. olivacea sp. nov.; ventral apodeme of parameral sheath often elongate, length equal to ejaculatory apodeme, rarely shorter; lateral ejaculatory apodeme present but not enlarged; ejaculatory apodeme narrow, elongate.

Female genitalia. Anterior process of tergite 8 narrow; three spherical spermathecae of equal size; spermathecal sac simple, spherical, without lobes; spermathecal ducts joining to common spermathecal sac duct; acanthophorite A1 setae well developed.

Comments

The shape of the gonocoxites and aedeagus indicates a close relationship between Acatopygia and Patanothrix . The banded wings and shape of the head and male genitalia are diagnostic for the genus. Acatopygia species are distributed throughout coastal south­eastern Australia. Acatopygia pulchella is common in southeastern Queensland while A. paradoxa is more common in southern New South Wales. Acatopygia olivacea sp. nov. is less common than the other two species in collections and is known from southern Queensland to Northern New South Wales.

Included species

A. olivacea sp. nov., A. paradoxa ( Kröber 1912b) , A. pulchella Kröber 1912 a.

Figures

FIGURE 1. Acatopygia olivacea sp. nov., male genitalia: A, epandrium, dorsal view; B, tergite 8, dorsal view; C, gonocoxites lateral view; D, same, ventral view; E, sternite 8, ventral view; F, aedeagus, lateral view; G, same, dorsal view. Abbreviations: c, cercus; d, distiphallus; da, dorsal apodeme of parameral sheath; ea, ejaculatory apodeme; ga, gonocoxal apodeme; gp, gonocoxal process; gs, gonostylus; h, hypandrium; igp, inner gonocoxal process; lea, lateral ejaculatory apodeme; va, ventral apodeme of parameral sheath; vl, ventral lobe. Scale line = 0.5 mm.

FIGURE 2. Acatopygia paradoxa (Kröber), male genitalia: A, epandrium, dorsal view; B, tergite 8, dorsal view; C, gonocoxites lateral view; D, same, ventral view; E, sternite 8, ventral view; F, aedeagus, lateral view; G, same, dorsal view, dorsal apodeme of parameral sheath removed. Female internal genitalia (after Winterton et al. 2001): H, dorsal view with external terminalia removed. Abbreviations: acc, accessory gland; f, furca; s, spermatheca; sd, spermathecal duct; ss, spermathecal sac; ssd, spermathecal sac duct. Scale line = 0.5 mm.

FIGURE 3. Acatopygia pulchella Kröber, male head: A, dorsal; B, same, lateral. Scale line = 0.5 mm.

FIGURE 4. Acatopygia pulchella Kröber, male genitalia: A, epandrium, dorsal view; B, tergite 8, dorsal view; C, gonocoxites lateral view; D, same, ventral view; E, sternite 8, ventral view; F, aedeagus, lateral view; G, same, dorsal view. Scale line = 0.5 mm.