Spicebush Swallowtail
Papilio troilus

f16 @ 1/400s, ISO:2500, Nikon D3S w 105mm macro

"Papilio troilus," Wikipedia, the free encyclopedia. The spicebush swallowtail or green-clouded butterfly, is a common black swallowtail butterfly found in North America. The female has a trademark bright blue splotch in the shape of a half moon on the hindwings.
East Falmouth, Massachusetts