A Zebra Swallowtail, Eurytides marcellus,
as portrayed in tiles on the walls of the West 77th street entrance to the NYC subway stop (A-B-C)
at 81st and Central Park West. (ISO, no zoom, no flash).
Actually it's a Zebra Swallowtail, and you are within its range when you are not hanging out in Kansas. Zebras fly mainly in the spring. If you cannot find one in the NYC area, hie yourself down to Houston. I can show you plenty of these around 100 miles ENE of here in the Big Thicket. Seeing Zebra Swallowtails is one of my favorite things about exploring the preserves around East Texas. I recommend Jim Brock's BUTTERFLIES OF NORTH AMERICA as an excellent field guide, and of course you never can have too many, so by all means also get Jeff Glassberg's BUTTERFLIES THROUGH BINOCULARS: THE EAST.