Key to genera of the Chaetopsis group (Lipsanini) 1. Frontal setae strong, usually 2–3 × longer than parafrontal setulae at eye margin. ........ (Amethysa + Aspistomella group + Chaetopsis group) ............................... 2 — Frontal setulae all short, same length as parafrontal setulae at eye margin. ......... ................ (Euxesta and other Lipsanini) 2. Abdomen elongate with narrow pleura, oviscape usually longer than tergites 4 and 5 combined, if shorter, then aculeus and especially its cercal unit dorsoventrally flattened; if not clear, then either interfrontal setae absent, or postpedicel apically pointed, or head conspicuously longer than high with face oblique and without epistome, or vein CuA+CuP entirely or partly reduced. .... Chaetopsis group ............................... 3 — Abdomen broadly oval with pleural membrane at least 0.3 × as wide as sternites 3–5, oviscape shorter than tergites 4 and 5 combined, aculeus and cercal unit oval in section, not flattened; neither interfrontal setae completely absent, nor postpedicel apically pointed; head always higher than long, face vertical, often with conspicuously or strongly protruded epistome; vein CuA+CuP well developed. .............. .......... (Amethysa + Aspistomella group) 3. Cell cua lacking; wing less than 0.25 as wide as long ............. Steneretma Loew — Cell cua present; wing usually broader than described above .......................... 4 4. Vein CuA+CuP entirely absent; if present, then shorter than half of cell cua ........................... Eumecosomyia Hendel — Vein CuA+CuP well developed, if shortened, then at least as long as cell cua .... 5 5. Head twice longer than high ................. ............................. Eumetopiella Hendel — Head almost as long as high or higher than long ............................................. 6 6. Ventral portion of face receding ........... .................................. Stenomyia Hendel — Ventral portion of face slightly to strongly protruding anteriorly ............ 7 7. Vein R 1 setulose along pterostigma. Aculeus apically pointed ...................... ................... Parastenomyia new genus 1 Nearly half of species assigned to Chaetopsis (see Steyskal 1968) differ from the “core” related to its type species and need a revision with phylogenetic analysis and refining concept of that genus. — Vein R 1 bare. Aculeus apically truncate (or if, in some Zacompsia, pointed, then ventral portion of face strongly protruding anteriorly, in front of anterior margin of frons) .............................................. 8 8. Ventral portion of face strongly protruding anteriorly, in front of anterior margin of frons .............. Zacompsia Coquillett — Ventral portion of face moderately protruding ................................................ 9 9. Interfrontal setae or setulae absent. Postpedicel acute .............. Chaetopsis Loew — Interfrontal setae present. Postpedicel either acute or rounded .. Species incertae sedis provisionally assigned to Chaetopsis 1

Published as part of Kameneva, Elena P., Korneyev, Severyn V. & Korneyev, Valery A., 2025, Parastenomyia New Genus (Diptera: Ulidiidae: Lipsanini) From Costa Rica, Ecuador, And Peru, pp. 485-500 in Proceedings of the Entomological Society of Washington 127 (3) on pages 494-495, DOI: 10.4289/0013-8797.127.3.485, http://zenodo.org/record/18484343