I saw this big beetle (~25 mm long) on a sidewalk yesterday in College Park, Maryland. It kept opening its wings, but couldn't get itself off the ground. I also see in the picture that it may have been missing most of its right front leg. I think my Pelidnota punctata had seen better days and was on its way out.
My insect books narrowed the identification down to a couple of species and then, using the abundant pictures on BugGuide.net, I was able to select the grapevine beetle as the correct one. I have also posted this picture here on BugGuide.net.
Note that the legs of this specimen were brown; if you go thru the pictures on BugGuide.net, you will notice that there is a variety (different species?) that has black legs.
As its name implies, the grapevine beetle is supposed to feed on grapes. But I found this outside of a small wooded area. I don't think there were any grape plants in the vicinity.
Note added in the evening: Coincidentally, Myrmecos Blog also had a Pelidnota punctata picture today. That specimen has black legs and the wing covers seem to be more orange than those of my specimen.