Detail of pronotum from individual previously photographed. Pardon the multiple images, but I'm trying to work out the species here. Quoting from Ciegler, Ground Beetles of South Carolina, p. 27 (1):

4(1) Pronotum with setigerous puncture near hind angle; lateral raised bead of pronotum sharply defined inwardly for its entire length---> C. sayi

Pronotum without basal setigerous puncture but with usual lateral one at midline; lateral bead obscure, at least basally ---> 5 (C. externum, C. calidum)

This should be C. sayi. Compare to the pronotum of another individual believed to be of that species: