Male-based key to genera for the subfamily Formicinae (Hymenoptera, Formicidae) in the Nearctic region.

Male ants remain one of the least documented sources of morphological information in ant taxonomy, despite their frequent occurrence in biodiversity surveys and their potential value for systematic research. Within the ant subfamily Formicinae, identification resources for male ants are particularly limited in the Nearctic region. The only comprehensive treatment remains Smith's (1943) key to male ants of the United States, which predates modern taxonomic revisions and advances in morphological terminology. In this work, a revised identification key to the genera of Nearctic Formicinae is presented, based exclusively on male morphology. An illustrated key to the 14 formicine genera recorded from the Nearctic region is provided, supported by updated diagnoses and figures of diagnostic characters, including genitalia and wing venation. This study provides the first modern synthesis of male morphological characters for Nearctic Formicinae and enables reliable identification of males, including specimens collected independently of workers in light traps, Malaise traps, and flight-intercept traps, thereby facilitating the broader integration of male morphology into taxonomic and biodiversity research on ants.