Another challenge to natural history experts out there. This is from North Carolina, and it is at 3-4X (in camera) magnification in the original, and cropped some here--so the final magnification is quite high. The big spot is about 1.5 mm wide. (see below for answer.) This was rather an accidental photo. The beetle banged into my kitchen window and I captured it. I put it on a stage of white craft foam and it hunkered down, refusing to pose in an alert posture. Frustrated, I put on my MP-E 65mm to work on a smaller beetle. I then decided to take a few detail shots of the Pelidnota, since it was cooperating so well.