RESUMO: The stability and universality of firefly taxonomy hinge on the lack of revisionary studies, such as those addressing the validity of taxon names, including widely used ones like Bicellonycha Motschulsky, 1853. This is one of five genera of predatory fireflies (Lampyridae, Photurinae), with 45 species distributed across the Americas. Motschulsky designated Lampyris albilatera Gyllenhal, 1817 as type species of Bicellonycha, but later suspicion by earlier taxonomists – including Laporte and Olivier – led McDermott to designate Bicellonycha deleta Motschulsky, 1854 as type, which remains undisputed. However, B. deleta was not available when Bicellonycha was described by Motschulsky a year earlier, and thus cannot be designated as the type species. In addition, the type material of B. deleta remains as a single elytron, and the original taxonomic description is insufficient to confidently identify it, raising instability further. Here, we address this pervasive nomenclatural issue of the typification of Bicellonycha. We confirm (i) the validity of Motschulsky’s typification of L. albilatera by original designation, and (ii) the longstanding suspicion that Motschulsky misidentified this genus’ type species, which lacks Photurinae diagnostic traits but fits Photinus (Lampyrinae: Lucidotini) seamlessly, instead. In accepting Motschulsky’s typification, we enforce an overlooked synonymy of Bicellonycha and Photinus (which takes priority) put forth by Lacordaire (1857), and describe Santiagonycha gen. nov. to encompass those 45 species previously placed in Bicellonycha. Santiagonycha lineola (Blanchard, 1845) comb. nov., designated as type species, is herein thoroughly redescribed from all life stages, to serve as reference for a future revision of this genus. Although we recognize this nomenclatural change brings about temporary instability, we are confident it sets the stage for a more solid lampyrid taxonomy.