We took these pictures four years ago, but had no clue what they were until lately we received "Owlet Caterpillars of Eastern North America," (Wagner et al., 2011), where we found a possible match with Cerathosia tricolor. Ours were feeding on the flowers of Indian Pink (Spigelia). We noted, however, that ours in eastern Arkansas were far to the east of the stated range, and we further noted ours had red head capsules, rather than the black pictured in the book, so possibly these represent a different species.