The Tachytrechus alatus species group (= Syntomoneurum Becker) revisited: new species and revised species group limits (Diptera: Dolichopodidae) Author Brooks, Scott E. Author Cumming, Jeffrey M. text Zootaxa 2008 1676 1 27 journal article 10.5281/zenodo.180314 59f2f391-287e-465d-b396-9d11cd0a3378 1175-5326 180314 Tachytrechus transversus (Van Duzee) (Figs. 8, 9, 12) Polymedon transversus Van Duzee 1929 : 52 . Tachytrechus transversus (Van Duzee) : Robinson, 1970 : 56 (catalogue). Diagnosis. Body length 5.5–6.2 mm , wing length 5.4–5.6 mm ; face and upper part of clypeus metallic greenish-coppery, abruptly pale yellow in lower part of clypeus, male clypeus with sharp medial and lateral carinae; palpus with large, stout seta on lower margin (Fig. 8A); 2 notopleural bristles; male fore tarsus unmodified; hind femur with 1 anterior preapical bristle; M with two strong obtuse bends in distal half; R4+5 and M parallel distally (Figs. 8B, 8C); male wing (Fig. 8B) with two adjacent flap-like costal swellings immediately proximal to insertion of R1; male tergite 5 with posterior membraneous region bordering and mostly confined to dorsal portion of sclerite ( Fig 9 A); male sternite 5 with large complex eversible glandular structure ( Figs. 9 A, 9B); hypopygium ( Figs. 9 C, 9D): right and left basiventral epandrial lobes well-developed, digitiform, projected dorsally and lying adjacent to medial surface of apicoventral epandrial lobes, apex of right lobe with 90° bend; apicoventral epandrial lobe flared apically, projected posteriorly; accessory epandrial process absent; ventral surstylar lobe with series of parallel diagonal ridges ventrally; apicolateral arm of postgonite lacking medial process, apex rounded, unmodified; cercus subquadrate in dorsal view, margin not darkened; hypandrium asymmetrical in ventral view, right margin with rounded process near middle; phallus with large fin along middle third, weak dentiform projection subapically. Female sternite 8 divided medially, lacking deep medial invagination. Type material examined. Holotype ɗ, GUATEMALA : Zacapa, El Jicara, 11.v.1926 ; J.M. Aldrich ( USNM Type No. 41062). Paratypes , 3Ψ, with same locality and collection date as holotype ( USNM ). Other material examined. 1ɗ, MEXICO : Chiapas, above Arriaga, over crest, 22.v.1963 , H. Robinson: 1ɗ ( USNM ). Distribution. Tachytrechus transversus is known from the type locality in Guatemala and also from a single male collected near Arriaga, Chiapas, Mexico ( Fig. 12 ). FIGURE 8. Tachytrechus transversus (Van Duzee) : (A) male head; (B) male wing; (C) female wing. Abreviations: A1: anal vein; CuA1: 1st anterior branch of cubital vein; dm-cu: discal medial-cubital crossvein; M: medial vein; pavt s: paravertical seta; plp s: palpal seta; R1: 1st radial vein; R2+3: 2nd + 3rd radial vein; R4+5: 4th + 5th radial vein; vt s: vertical seta.