Rachicerus Walker 1854

Genus Rachicerus Walker, 1854 Rachicerus. Nomen nudum. Walker, 1848: 124. Attributed to Haliday. Rachicerus Walker, 1854: 103. Type species, Rachicerus fulvicollis Walker, 1854, by monotypy. Rhyphomorpha Walker, 1861: 275. Type species, Rhyphomorpha bilinea Walker, 1861, by monotypy. Antidoxion Snellen van Vollenhoven, 1863: 6. Type species, Antidoxion fulvicorne Snellen van Vollenhoven, 1863, by monotypy. Syn. by Osten Sacken, 1881: 409. Rhachicerus. Unjustified emendation of Rachicerus Walker. Loew, 1872: 114. Antidoxia. Incorrect subsequent spelling. Marschall, 1873: 321. Rhacicerus. Incorrect subsequent spelling. Malloch, 1917: 346. Rhachicerella Enderlein, 1921: 167. Type species, Rachicerus honestus Osten Sacken, 1877, by original designation. Syn. by Nagatomi, 1970: 418. Rachicerella. Incorrect subsequent spelling. Carrera, 1945: 120. Gymnorhachicerus Frey, 1954: 7. Type species, Gymnorhachicerus pilosus Frey, 1954, by original designation. Syn. by Woodley, 2011: 476. Diagnosis. Small to medium-sized flies; head hemispherical; frontal plate large, strongly depressed; compound eyes dichoptic and bare in males and females; the upper inner margin of the compound eyes, above the insertion of the antennae, with a triangular orbital area, without ommatidia or pilosity, adjacent to the fronto-orbital plate; antennal flagellum highly modified slightly to strongly pectinate, or bipectinate, composed of 15 up to 35 flagellomeres. Thorax with mesonotum (scutum) and scutellum unmodified; postpronotal lobe and laterotergites bare. Wings hyaline to infuscate, mainly around the longitudinal veins; between Sc and R 1 sometimes, there is an inconspicuous dark macula pterostigma-like; between veins R 1 and R 2+3 there is a small and inconspicuous hyaline spot; R S stem vein curved upwards before the bifurcation of the radial sector; distal end of M vein transparent or whitish, covered by a dense microtrichia; cell m 3 closed at wing margin. Legs unmodified, long and slender, tibial spurs 1:2:2. Abdomen slender, with seven to nine visible segments; about as wide as thorax, only slightly tapered posteriorly in males, whereas in females the apical segments are moderately elongate and strongly narrowed posteriorly (ovipositor-like).