This carabid ran across a concrete pad right under my feet as I was helping with a class for park rangers and educators on beetles. I picked it up, showing it off, thinking it was a Bombardier Beetle, Brachinus. Oops--I should have known better than to call a carabid so quickly. I photographed it in detail and realized it was something in the big, confusing subfamily Harpalinae. Barking up a couple more wrong genera, I realized it was Amphasia interstitialis, based on the description and keys in Janet Ciegler's Ground Beetles...of South Carolina. The pattern of punctures and hairs on the elytra, the pronotal shape and punctures, and big spur on the front tibia all line up with this species. (See also this helpful page on beetles of the Great Smokies.) Length about 10 mm. This experience reminds me why I seldom try to identify carabids!