Figures 1-12. Generic diagnostic characters of Mycomystes Gorham, 1888: (1) Head of M. peruvianus (Kirsch, 1876), arrow showing the complete clypeal marginal bead. (2) Subgenal braces of M. coccineus (Lacordaire, 1842), arrow showing the inner carina. (3) Partial view of the mouthparts of M. coccineus, big arrows showing the apical maxillary palpomeres and small arrow showing an apical labial palp. (4) Right mandible of M. nigriventris Pecci-Maddalena and Lopes-Andrade, 2020, arrow showing the teeth. (5–6) Mentum plate of M. coccineus and M. melanophthalmus (Duponchel, 1825), respectively. (7) Partial view of the pronotum and elytra of M. apicalis (Lacordaire, 1842), arrows showing the basal elytral marginal bead. (8–9) Mesotibia of M. apicalis and M. melanophthalmus, respectively. (10–11) Metendosternite of M. melanophthalmus and of a male of M. coccineus, respectively, arrow in Figure 10 showing the anterior tendon. (12) Abdomen of M. peruvianus, arrows showing the coxal lines. Scale bars: 0.1 mm (2, 4–6, 10–11); 0.25 mm (8–9); 0.5 mm (3, 7).