Oh, I'm having trouble telling them apart.

On the Comma, the size is a tad smaller, there is one less prominent rounded dark spot toward the end of the front wing in the top side, and usually the "comma mark" on the under hind wing is not broken. The wings tend to be a bit more irregular (or "ragged" looking) along the outer margin, and the banding on the under side is more irregular.

The Question mark is larger, usually a little "smoother" looking because the markings below tend to be less irregular, as does the outer wing margin. The largest point that sticks out from the front wing is usually noticeably longer. The "comma mark" is usually broken and so very like a "question mark" in shape.

Something that doesn't help is how bold the markings are below, nor how black the hind wings are above. There are light and dark seasonal forms of both species. The pattern on the underside can be fairly contrasting and bold; or, it can be nearly even and plain (usually the plain ones are female in the Comma, but they can be male or female in the Question Mark). I think this one is male, but I'm not certain.

In areas where there are three or four species of Polygonia it gets more complicated, but all the others are more like the Comma than like the Question Mark.

Thank you. I've been going through my various photos and think I have them all ID'd correctly now. I do have some of a comma that is lighter in color than this one.