Underside, obviously... this guy's top side is hard black, and hides wings like a ladybug's wings are stowed. It's about 3/16" long, about half as wide as you can see from the picture, and maybe as tall as half that again.
I've been wondering, because I've seen an unusual number of these guys this season. There's about ten, dried and dead by now, sitting near the window (clean the place? Gnaw, not me!). One day I found one circling and circling the rim of a Dixie cup that was laying on the floor, they don't seem to like walking off edges and don't fly much (I didn't realize they had wings until I poked this one, actually).
Tim