Two new species of Riethia Kieffer, 1917 from Chile and Ecuador (Chironomidae: Chironominae, Pseudochironomini) Author Andersen, Trond 0000-0003-2201-1870 University of Bergen, University Museum of Bergen, Department of Natural History; P. O. Box 7800, NO- 5020 Bergen, Norway. trond.andersen@uib.no Author Malla, Annui 0000-0003-0580-6890 University of Bergen, University Museum of Bergen, Department of Natural History; P. O. Box 7800, NO- 5020 Bergen, Norway. annui.parra@uib.no Author Giłka, Wojciech 0000-0002-8403-5432 University of Gdańsk, Faculty of Biology, Department of Invertebrate Zoology and Parasitology, Laboratory of Systematic Zoology; Wita Stwosza 59, 80 - 308 Gdańsk, Poland. wojciech.gilka@ug.edu.pl text Zootaxa 2024 2024-05-14 5448 4 499 507 http://dx.doi.org/10.11646/zootaxa.5448.4.3 journal article 296651 10.11646/zootaxa.5448.4.3 1002ac3f-0588-4994-ab47-064079c5bf32 1175-5326 11232202 97D81822-3B9A-4A25-99ED-F8DC6AE1436B Updated key to Neotropical males of Riethia 1. Posterior margin of tergite IX with caudal projections resembling an inverted U ( Brazil )........................................................................................ .. R. fazzari Trivinho-Strixino & Shimabukuro, 2018 - Posterior margin of tergite IX straight or rounded, without caudal projections..................................... 2 2. Superior volsella short, hook-like; inferior volsella subtriangular, tapering to narrowly rounded apex; with few, scattered, flattened, apically pectinate dorsal setae and 2–3 marginal scales apically ( Brazil )............................................................................................... R. galilei Trivinho-Strixino & Shimabukuro, 2018 - Superior volsella long, curved or with distal half straight, digitiform; inferior volsella not subtriangular and tapering to narrowly rounded apex, with or without flattened, apically pectinate dorsal setae and/or marginal scales........................ 3 3. Inferior volsella strongly bent dorsally with apical part bluntly subtriangular with more than 20 broad flattened, apically pectinate setae covering dorsal surface, without marginal scales................................................ 4 - Inferior volsella not strongly bent dorsally, with marginal scales; without or with less than 20 broad flattened, apically pectinate setae............................................................................................... 6 4. Legs with dark bands; superior volsella curved, digitiform, apically pointed with microtrichia and apparently 2 weak, dorsal setae subapically ( Argentina , Brazil , Chile )................................... R. truncatocaudata ( Edwards, 1931 ) - Legs without dark bands; superior volsella curved, stout, with long, narrowly triangular apex, with or without microtrichia, with 5–7 weak, dorsal setae................................................................................. 5 5. Abdomen brown, without dark bands; superior volsella with scattered microtrichia ( Ecuador )..... R. ecuadoriensis sp. nov. - Abdomen light brown, tergites with darker brown oral bands; superior volsella without microtrichia ( Chile )................................................................................................. R. chilensis sp. nov. 6. Superior volsella with distal half straight; inferior volsella with about 10 broad scales in double row along inner margin, without broad, flattened, apically pectinate setae ( Costa Rica ) ......................... R. epleri Andersen & Sanz-laParra, 2023 - Superior volsella curved; inferior volsella with both marginal scales and broad, flattened, apically pectinate setae......... 7 7. Acrostichals absent; clypeus with less than 10 setae ( Brazil )........... R. cauame Trivinho-Strixino & Shimabukuro, 2018 - Acrostichals present; clypeus with more than 25 setae........................................................ 8 8. Inferior volsella with 15 broad, flattened, apically pectinate setae dorsally and 3 broad marginal scales apically ( Brazil )............................................................. R. manauara Neubern, Trivinho-Strixino & Silva, 2011 - Inferior volsella with 6 broad flattened, apically pectinate setae dorsally and 7 broad marginal scales apically ( Brazil ).................................................................. R. pantera Trivinho-Strixino & Shimabukuro, 2018