Key to Genera and Subgenera of Ephydrini Zetterstedt 1. Prosternum setulose on at least posterior portion. Pulvilli much reduced or absent; tarsal claws long and nearly straight..... 2 - Prosternum bare. Pulvilli well developed; tarsal claws short and distinctly curved.................................. 11 2. Basal flagellomere bearing a large lateral seta just below insertion of arista........................... Setacera Cresson - Basal flagellomere without a lateral seta.................................................................... 3 3. 3 or more well-developed fronto-orbital setae. Anterior presutural supra-alar seta usually well developed, subequal to notop- leural setae........................................................................................... 4 - 2 well-developed fronto-orbital setae present. Anterior presutural supra-alar seta absent or much reduced, much smaller than posterior notopleural seta............................................................................... 7 4. 5–6 well-developed fronto-orbital setae..................................................... Neoephydra Mathis - 3–4 well-developed fronto-orbital setae.................................................................... 5 5. 2 presutural dorsocentral setae, anterior seta sometimes rather short. Face very thickly setulose; arista short, weakly haired, thicker on its basal half; usually 2 posteriorly directed rows of well-developed cruciate interfrontal setae present, with these rows closer to orbital setae than to each other. Male with basitarsomere of foreleg bearing ventral tuft of long setulae near tip............................................................................ Ephydra (Hydropyrus Cresson) - 1 presutural dorsocentral seta. Face with 1 well-developed row of facial setae and 1 of oral setae, otherwise thinly short-haired; arista without markedly swollen basal region; usually not more than 1 pair of interfrontal setae situated as close to each other as to orbital setae. Male with basitarsomere of foreleg without ventral tuft of setulae................................ 6 6. 1 well-developed interfrontal seta present; palpus well developed. Crossvein dm-cu making nearly a right angle with vein CuA l................................................................................ Ephydra (Ephydra Fallén) - Interfrontal seta weak or absent; palpus small. Crossvein dm-cu forming an acute angle with vein CuA l................................................................................................ Ephydra (Halephydra Wirth) 7. Cruciate interfrontal setae present......................................................................... 8 - Cruciate interfrontal setae absent........................................................................ 10 8. Dorsocentral setae 4 (1+3). Arista bearing subpectinate dorsally-branching rays on basal 1/2.......... Paraephydra Mathis - Dorsocentral setae 5 (1+4). Arista at most minutely haired on basal 1/2........................................... 9 9. Aristal rays long, length subequal to width of pedicel. Hindfemur of male not differing markedly from fore- or midfemur, lacking stout setae as above; hindtibia of male lacking tuft of setulae; hindtarsi of male cylindrical, normal.. Dimecoenia Cresson - Aristal rays short, length approximately 1/2 width of pedicel. Hindfemur of male conspicuously swollen, bearing short row of 4–5 stout setae along anteroventral surface toward base; hindtibia of male with ventroapical tuft of setulae; hindtarsi of male variously modified......................................................................... Cirrula Cresson 10. A well-developed prescutellar acrostichal seta; 2 postpronotal setae, dorsal seta about 1/2 length of ventral seta; prosternal setulae few (Australasian)........................................................ Ephydrella Tonnoir and Malloch - Lacking a well-developed prescutellar acrostichal seta; 1 postpronotal seta; prosternal setulae numerous (Neotropical)........................................................................................... Neoephydra Mathis 11. Dorsocentral setae 4 (1+3) present; postpronotal seta(e) either weak, at most 1/4 length of posterior notopleural seta, or lacking. Hindcoxa bare posteriorly.......................................................................... 12 - Dorsocentral setae 5 (1+4) present (anterior setae reduced in Austrocoenia); postpronotal seta distinct, at least 1/2 as long as posterior notopleural seta. Hindcoxa bare or with a row of setae posteriorly....................................... 13 12. Arista bearing long hairs dorsally, length of longest hairs subequal to height of basal flagellomere; frons only moderately to sparsely microtomentose, especially subshiny mesofrons (Holarctic)........................ Coenia Robineau-Desvoidy - Arista either almost bare or bearing short hairs dorsally, length of longest hairs about 1/2 height of basal flagellomere; frons uniformly and densely microtomentose, dull, mesofrons little differentiated from parafrons............................ (Neotropical).......................................................................... Notiocoenia Mathis 13. Paravertical seta large, at least 1/3 length of medial vertical seta................................................ 14 - Paravertical seta small, generally subequal to setae of postocular row........................................... 16 14. R stem vein bearing 1–2 setulae dorsally, inserted beyond transverse septum. Scutellar disc convex. Hindcoxa with row of setae along posteroventral margin.......................................................... Paracoenia Cresson - R stem vein bare dorsally. Scutellar disc almost flat. Hindcoxa bare posteriorly along ventral margin (Genus Calocoenia Mathis)............................................................................................ 15 15. Larger species, body length over 3.25 mm. Gena-to-eye ratio 0.25 or larger. Costal setulae well developed, projected anteriorly from ventral and dorsal surfaces................................................... Subgenus Calocoenia Mathis - Smaller species, body length under 2.75 mm. Gena-to-eye ratio 0.20 or smaller. Costal setulae weakly developed, only on dorsal surface....................................................................Subgenus Leptocoenia Mathis 16. Frons mostly lacking setulae and with coloration and vestiture generally uniform, microtomentose, dull; arista long, nearly double length of basal flagellomere. 1 interalar seta inserted just posterior of transverse suture.......... Notiocoenia Mathis - Mesofrons tan to brown, generally distinct from grayer parafrons, microtomentum denser, conspicuously setulose, especially laterally; arista short, subequal to length of basal flagellomere. Interalar seta lacking................. Austrocoenia Wirth

Published as part of Mathis, Wayne N. & Marinoni, Luciane, 2016, Revision of Ephydrini Zetterstedt (Diptera: Ephydridae) from the Americas south of the United States, pp. 1-110 in Zootaxa 4116 (1) on pages 7-8, DOI: 10.11646/zootaxa.4116.1.1, http://zenodo.org/record/257322