Welcome back Mr. Rudkin: differentiating Papilio zelicaon and Papilio polyxenes in Southern California (Lepidoptera: Papilionidae).

We studied wing pattern characters to distinguish closely related sympatric species Papilio zelicaon Lucas, 1852 and Papilio polyxenes Fabricius, 1775 in Southern California, and developed a morphometric method based on the ventral black postmedian band. Application of this method to the holotype of Papilio [Zolicaon variety] Coloro W. G. Wright, 1905, the name currently applied to the P. polyxenes populations, revealed that it is a P. zelicaon specimen. The name for western US polyxenes subspecies thus becomes Papilio polyxenes rudkini (F. R. Chermock, 1981), reinstated status, and we place coloro as a junior subjective synonym of P. zelicaon. Furthermore, we sequenced mitochondrial DNA COI barcodes of rudkini and coloro holotypes and compared them with those of polyxenes and zelicaon specimens, confirming rudkini as polyxenes and coloro as zelicaon.