Apologies for poor image quality; this butterfly evidently wasn't ready for its close-up.

Does this look like a summer azure (Celastrina neglecta)? I don't see any records for October on BugGuide for any state, which makes me question it.

I have seen Eastern tailed blues here this late in the season, but this butterfly had no tails and no discernible orange spots. Although I didn't get a dorsal picture, there may be a hint of the dark ring around the top of the forewing on the dorsal side visible through the folded wings...or maybe it's my overactive imagination. The photo of the other side of this individual looks like a bit of the hindwing is missing, and the bit of dorsal hindwing showing looks light in color, without the orange markings of a tailed blue. Could this be an unusually persistent summer azure? [EDIT: John Ascher thinks so.]

This butterfly was photographed shortly before 6:00 PM on a warm, mostly-sunny afternoon, mostly flying, but stopping briefly on boneset, snakeroot, and aster (pictured here) plants to drink.

[EDIT: BaMoNA's description suggests flight through October, so maybe it's not so outlandish.]