Doug Wechsler / Tiger swallowtail butterfly {Papilio glaucus} female resting on trumpetweed. USA.

LYNN M. STONE / Eastern Tiger Swallowtail butterfly (Papilio glaucus), male, feeding on nectar of Pink Thistle, Illinois, USA

LYNN M. STONE / Eastern Tiger Swallowtail butterfly (Papilio glaucus), dark phase female, on Pink Thistle in tallgrass prairie remnant, Illinois, USA (an intermediate phase between the typical yellow and the entirely...

Jerry Monkman / Eastern tiger swallowtail butterfly {Papilio glaucus} Sabins Pasture, Vermont, USA

Doug Wechsler / Male Tiger swallowtail {Papilio glaucus} feeding on Buddleia flowers, Pennsylvania, USA.

Doug Wechsler / Tiger swallowtail butterfly (Papilio glaucas) feeding. Philadelphia, USA

Doug Wechsler / Tiger swallowtail butterfly, Virginia USA