Phylogeny and Taxonomy of the Risa Genus-group (Diptera: Ephydridae), with Description of a New Genus from Australia Author Mathis, Wayne N. Department of Entomology, PO BOX 37012, MRC 169, Smithsonian Institution, Washington, DC 20013 - 7012, United States of America Author Zatwarnicki, Tadeusz Institute of Biology, Opole University, ul. Oleska 22, 45 - 052 Opole, Poland text Records of the Australian Museum 2023 Rec. Aust. Mus. 2023-03-15 75 1 1 23 http://dx.doi.org/10.3853/j.2201-4349.75.2023.1823 journal article 10.3853/j.2201-4349.75.2023.1823 2201-4349 7946210 Key to species of Risa Becker 1 Palpus yellow ............................................................................................................................ 2 —— Palpus black ............................................................................................................................... 3 2 Forecoxa black. Ocellar triangle short, slightly protruding beyond middle of frons. Postocellar setae present .................................... R. flavipalpis Ozerov —— Forecoxa yellow. Ocellar triangle long, reaching lunule. Postocellar setae absent .............................................................. R. flavicoxa Krivosheina & Ozerov 3 Fronto-orbital setae 3 (rarely 2 or 4), proclinate, small, hair-like, equal or subequal in size ( Figs 22 , 38, 39 , 49, 50 , 57–60 ) ........................................................ 4 —— Anterior fronto-orbital seta about 2–3 times longer than middle fronto-orbital seta, inclinate; posterior fronto-orbital seta usually reclinate, occasionally proclinate, usually as long as anterior fronto-orbital setae, occasionally as long as middle fronto-orbital seta ( Figs 21 , 26, 27 ) ........................................................................................... 9 4 Labellum about twice length of ventral margin of head in lateral view ( Figs 24 , 46 ) ...................................................................................................................... 5 —— Labellum about 1–1.5 times length of ventral margin of head ( Figs 23, 25 , 40, 41 , 58 ) ............................................................................................................ 8 5 Prescutellar acrostichal setae well developed; scutellar disk bearing scattered, sparse setulae; setulae along costal margin numerous; large species (length about 2 mm ) ............................................... R. asiatica Ozerov —— Prescutellar acrostichal setae greatly reduced or lacking ( Fig. 37 , 59–60 ); scutellum lacking setulae; setulae along costal margin sparse; smaller species (length about 1–1.5 mm ) ...................................................................... 6 6 Scutum distinctly microtomentose; setulae along costal margin more numerous and denser (24–34 on distalmost section). Halter knob with large dark spot .......................................................... R. brevicornis Papp comb. nov. —— Scutum indistinctly microtomentose; setulae along costal margin fewer and sparser (11–16 on distalmost section). Halter knob entirely yellow or with large dark spot ............................................................................. 7 7 Antenna and arista predominantly brownish ( Fig. 37 ). Halter knob yellow ...................................................... R. salsolae (Mathis & Zatwarnicki) comb. nov. —— Antenna predominantly or entirely yellow, scape and pedicel and basal flagellomere anteroapically occasionally darker, arista yellow to brown ( Figs 49, 50 ). Halter knob with large dark spot ........................................................................................................... R. nettae sp. nov. 8 Face nearly flat, without prominent shallow/low carina ( Fig. 58 ); antenna elongate, basal flagellomere ratio 1.75; scutum distinctly microtomentose ( Figs 59, 60 ); lower portion of frons, parafacial and lateral margin of face conspicuously and finely whitish to silvery microtomentose ( Figs 57, 60 ) ............................................................ R. kotrbae sp. nov. —— Face with distinct carina ( Figs 38, 39 ); antenna short, basal flagellomere ratio 1; scutum practically without microtomentum; lower position of frons, parafacial and lateral margins of face almost bare of microtomentum, shiny ( Figs 38, 39 ) ............................................................................................ R. brevirostris sp. nov. 9 Proboscis short, labellum about 1.25 times length of ventral margin of head ( Fig. 25 ); antenna elongate, basal flagellomere ratio 2.5–3 ( Fig. 25 ) ................................................................................... R. longicornuta Papp —— Proboscis long, labellum about 1.5 times length of ventral margin of head ( Figs 23 , 40, 41 ); antenna shorter, basal flagellomere ratio 2 ( Figs 23 , 26, 27 ) ............................................................................ R. longirostris Becker