Papilio polyxenes Fabricius, 1775

Also known as Black Swallowtail. Back on the day it snowed, just outside our mudroom, this popped out of its chrysalis:


It took me a while to find a way to identify it, but I did.
Check out this link. If you have a butterfly of unknown name on your hands, you can input whatever information you have (a hundred details about the wing shape or the coloring), and it will give you a short list of butterfly species that match. When I put in my information (nothing more than what can be observed in the picture), the site narrowed the 1198 species they cover to just 16. I compared their pictures of these 16 to my picture to figure out which one hatched out back.

I was able to find the proper name for it and where it lives and a lot of other stuff, most of which can be read here. I think I consulted the same source last fall, and learned that the caterpillars in our yard were going to become Monarch Butterflies . . .