Forest-dwelling myrmeleontids are often inadequately known and poorly represented in collections, impeding the study of their affinities and ecology. An exceptional example is the Neotropical species Ripalda insignis (Rambur, 1842), described on a single specimen and never observed again for more than 170 years. The recent rediscovery of this species in Paraguay allowed us to include it in a broader phylogenetic context of the antlion tribe Nemoleontini. Our morphology-based phylogenetic reconstruction, including both adult and larval characters, supports the synonymisation of the genus Araucaleon Banks, 1938 with Ripalda Navás, 1915, as the members of these genera form a well-supported clade. Ripalda appears to be related to the diverse genus Eremoleon Banks, 1901 and the small genera Sericoleon Esben-Petersen, 1933, Navasoleon Banks, 1943 and Elachyleon Esben-Petersen, 1927. The genus is also revised in light of a new cladistic framework, redescribing the three previously known species, R. insignis (Rambur, 1842), R. withycombei (Esben-Petersen, 1927) and R. inca (Banks, 1938) and naming a new species, R. wayana, sp. nov. from French Guyana. The larva of R. withycombei is also described for the first time. Larval morphology is broadly consistent with Eremoleon, also sharing a similar ecological niche.