Key to Compsodactylus species Modified from Fuhrmann 2012 and using data of Figueroa & Neita-Moreno 2019. Males do not have metatibiae spurs while females have two metatibial spurs (see remarks above). 1. Metafemur of males greatly widened and about three times wider than width of medial area of metatibia; females with gonostylus............................................................................................... 2 - Metafemur of males slightly widened and less than two times the width of the medial area of the metatibia (Figs. 12, 15); females without gonostylus............................................................................... 3 2. Pronotum and elytra with metallic green reflection; apex of protarsomere I of males slightly wider than apex of II, metatarsus of males somewhat moniliform; pygidium of males with scale-like setae; females with distal gonocoxite somewhat trapezoid or oval; Peru (Apurímac; Fig. 98).................................................... C. martinezi (Frey, 1972) - Dorsal surface without metallic green reflection; apex of protarsomere I of males twice wider than apex of II or almost so, metatarsus of males somewhat filiform; pygidium of males with hair-like setae; females with distal gonocoxite coma-like; Peru (La Libertad; Fig. 98)............................................... C. vallejoi Figueroa & Neita-Moreno, 2019 3. Elytral striae strongly and regularly punctate; metatibia of males gradually enlarged (Fig. 12); females with inner distal area of gonocoxite rounded; Argentina (Catamarca, Salta, Tucumán; Fig. 98)...................... C. argentinus (Moser, 1919) - Elytral striae shallowly and irregularly punctate; metatibia of males abruptly enlarged in proximal third (Fig. 15); females with inner distal area of gonocoxite straight; Bolivia (Cochabamba, Santa Cruz; Fig. 98).............. C. parvulus (Frey, 1970)

Published as part of Fuhrmann, Juares, 2019, Taxonomy of Neotropical genera Compsodactylus and Dasyus and notes on claw movement in Macrodactylini (Coleoptera: Scarabaeidae: Melolonthinae), pp. 139-163 in Zootaxa 4679 (1) on page 141, DOI: 10.11646/zootaxa.4679.1.9, http://zenodo.org/record/3466340