Sarginae Walker 1834

Key to Australian Sarginae genera

1 Wings with R 2+3 arising proximal to or above r-m; membranous strap-like lobe absent at base of wings; yellowish brown flies, usually not metallic................................................................................................................... 2

—— Wings with R 2+3 arising distal to r-m, usually beyond discal cell; membranous strap-like lobe present at base of wings; metallic flies.............................................................................................................................. 3

2 Frons wide and almost parallel in females; face slightly anteroventrally produced to form a small beak-like protuberance visible in profile view; scutum with a distinct black medial vitta; wings with vein M weak and nearly unpigmented between cells br and bm, M 1 and M 3 very weakly developed, M 4 connected to discal cell (i.e. dM 3+4 absent); alula reduced, almost linear (Fig. 4)..................................................................................... Formosargus James, 1939

—— Upper frons converging ventrally in females; face evenly rounded in profile view; scutum concolorous yellowish brown (Figs 9, 10) or dully metallic (P. longipes; Figs 7, 8), without any distinct markings; wings with vein M noticeably pigmented between cells br and bm, M 1 and M 3 well developed, M 4 separated from discal cell at least slightly by dM 3+4 ; alula large and apically expanded............................................................................... Ptecticus Loew, 1855

3 Head anteriorly produced in dorsal view, more circular and less than 1.5 times as wide as high in frontal view; occiput narrowly visible in dorsal view, with a prominent, posteriorly projecting fringe of hair-like setae; frons extremely narrow in females (index> 4), narrowly dichoptic in males by width of anterior ocellus; frontal ocellus distant from posterior ocelli, forming an elongated triangle; wings with all medial veins strong; CuA strongly curved, petiole vein CuA+CuP relatively long; apical half of alula set with microtrichia; abdomen slender elongate, about twice as long as wide (Figs 11–15).............................................. Sargus Fabricius, 1798 —— Head anteroventrally compressed in dorsal view, more than twice as wide as high in frontal view; occiput well developed and visible in dorsal view in females, both sexes without an obvious posteriorly projecting fringe of hair-like setae; frons wide in females (index <2), holoptic in males; ocelli forming an equilateral triangle; wings with at least some faint medial veins; CuA relatively straight, petiole vein CuA+CuP short; surface of alula bare of microtrichia; abdomen short, broad and ovoid, about 1.2–1.4 times as long as wide.......................................................................................... 4

4 Small species (length <6 mm); head more rounded in anterior view, about 0.75 times as high as wide; lower frons without distinct triangular callus; wing cell r 1 stained yellow; all medial veins faint (Figs 5, 6)........................................................................... Microchrysa Loew, 1855

—— Medium sized species (length ≥ 6 mm); head dorsoventrally compressed in anterior view, about 0.6 times as high as wide; lower frons with a distinct triangular callus diverging ventrally towards base of antennae; wing cell r 1 stained brown; veins M 2 and M 4 strong (Fig. 3)................................................................... Cephalochrysa Kertész, 1912