|Do you see the caterpillar, too? He'll be a black swallowtail, too!|
The Black Swallowtail has a number of names, American swallowtail, parsnip swallowtail, parsley swallowtail, celeryworm, and caraway worm (Miller 1992). It is a common butterfly, but I wasn't sure that I had ever noticed one before. The black swallowtail is found throughout southern Canada, most of the eastern and mid-western United States west to the Rocky Mountains, and southwest into Arizona and northern Mexico.
One can tell the males from the females by looking at the wings. On the upper part of the wings the two rows of yellow spots are large on the males and smaller and lighter in females. The part between the rows of spots is iridescent blue on the females.
I've seen some other butterflies as well.