NPSpecies

The hindwing should have more blue than the Desert Swallowtail, Papilo polyxenes coloro. In P. p. coloro the outside row of yellow spots on the fore-wings are rounded outward, where the P. zelicaon has the yellow spots flatter on the out edge. Both species have the pupil of the hindwing eye spot centered, whereas Papilio machaon bairdii brucei would have a wide pupil that touches the inside black margin of the wing. P. zelicaon is flat along the outer edge of the forewings center field. They appear to be a North Rim butterfly, larvae feeding on parsley from below the rim and adults hill topping at the rim. The month of June is the known flight period.