I'm still playing catch-up with this weekend's wildlife, but when I was all sleep deprived at the barbecue at Monty's, I caught sight of movement inside the porch. It turned out to be a butterfly that had come in the lower window and was spending time bashing himself against the glass.
I caught him easily in my cupped hands, and to my surprise he didn't fly away at the first chance, so Mark and Amy got out cameras and took pictures (this is Mark's picture). We taunted him with the tray of cantalope with no result.
There's no doubt about this specimen being a question mark (Polygonia interrogationis). Among my initial confusion is that the summer brood has a much darker hind wing, than the brood that's migratory and over-winters.