Based on the six eyespots, I am guessing this is a polyphemus moth. As I delved into the world of moths, I was amazed at the number of variations of size, color and distribution of these spots on the wings of moths. If you know something I don't, please weigh in here.
Update: I should just admit I don't have a clue and ask my resident nature expert before I post. The correct species is Buckeye Butterfly. I didn't even get butterfly, not moth right.