Hard to tell, just guessing: pearl crescent, tiger swallowtail?
Someone will be along with positive ID.
I'll second that!
I'll third that - pearl crescent, black female tiger swallowtail.
I'll fourth that. Good idea to give us a state in your "posted by" section. That helps us figure out just exactly what you might have. Your zone tells us how cold you get in the winter.
Pearl Crescent, Phyciodes tharos
Eastern Tiger Swallowtail, Papilio glaucu