RESUMO: Megalodacne Crotch, 1873 comprises over 150 species distributed across five subgenera. To date, no comprehensive taxonomic revision or phylogenetic study has been published for the genus. For future taxonomic and phylogenetic research, it is essential to gather detailed information on primary type specimens and to identify morphological characters with potential taxonomic value. In this study, we: (i) provide detailed information on the type specimens of Neotropical and Nearctic Megalodacne species; (ii) present images of these specimens or, when unavailable, of representative specimens to illustrate each species; and (iii) identify and discuss morphological characters with potential value for future taxonomic and phylogenetic studies. Additionally, lectotypes are designated for Dacne audouini Lacordaire, 1842, Megalodacne batesi Crotch, 1876, Dacne multifida Lacordaire, 1842, Ips fasciata Fabricius, 1777, and Episcapha heros Guérin-Méneville, 1841 (a junior synonym of Megalodacne indica indica (Linnaeus, 1758)). Megalodacne indica multifida (Lacordaire, 1842) is proposed as a new junior synonym of M. indica indica.