Heraclidesrumiko Shiraiwa & Grishin, sp. n. is described from southwestern United States, Mexico, and Central America (type locality: USA, Texas, Duval County). It is closely allied to Heraclidescresphontes (Cramer, 1777) and the two species are sympatric in central Texas. The new species is diagnosed by male genitalia and exhibits a nearly 3% difference from Heraclidescresphontes in the COI DNA barcode sequence of mitochondrial DNA. The two Heraclides species can usually be told apart by the shape and size of yellow spots on the neck, by the wing shape, and the details of wing patterns. "Western Giant Swallowtail" is proposed as the English name for Heraclidesrumiko. To stabilize nomenclature, neotype for Papiliocresphontes Cramer, 1777, an eastern United States species, is designated from Brooklyn, New York, USA; and lectotype for Papiliothoas Linnaeus, 1771 is designated from Suriname. We sequenced DNA barcodes and ID tags of nearly 400 Papilionini specimens completing coverage of all Heraclides species. Comparative analyses of DNA barcodes, genitalia, and facies suggest that Heraclidesoviedo (Gundlach, 1866), reinstated status, is a species-level taxon rather than a subspecies of Heraclidesthoas (Linnaeus, 1771); and Heraclidespallas (G. Gray, ), reinstated status, with its subspecies HeraclidesPapiliobajaensis (J. Brown & Faulkner, 1992), comb. n., and Heraclidesanchicayaensis Constantino, Le Crom & Salazar, 2002, stat. n., are not conspecific with Heraclidesastyalus (Godart, 1819).
Keywords: APHIS; Biodiversity; DNA barcodes; Heraclideshomothoas; Heraclidesmelonius; Neotropical; butterfly release; cryptic species.