Detail of head, pronotum, while restrained gently. Eyes are large, for a member of this genus, a characteristic of C. vigilans, Harpootlian, p. 12, fig. 13.
(1) Quoting from the description in
Scarab Beetles of South Carolina,
(1):
"
Canthon vigilans LeConte 1858:16. 13-20 mm. Black, with slight purple hue in many specimens. Densely granulate with mixed small and large granules. Clypeus deeply bidentate, teeth subtriangular; eyes large."
The photo seems to fit the description. Corrections and comments always welcome.
Compare with the eyes of what I think is another
Canthon vigilans:
