What kind of caterpillar is feeding on this buckeye leaf?
This is the caterpillar of the morning glory prominent moth (Schizura ipomaeae). While the adult moth is rather nondescript, the caterpillar is very interesting. It is quite well camouflaged, and from a distance, it could be mistaken for necrotic tissue along the margin of a leaf. Morning glory prominent caterpillars feed on the leaves of maples, oaks, elms, buckeyes, and several other trees common to the Southeast. Though some sources list morning glory plants as a host (hence their common name), other sources state this may not be the case. Read more about the morning glory prominent here.