Found south of Atsion lake in an area that had experienced a significant wildfire the year before. The caterpillars were seen on two consecutive days in the same place and on the same plants. Earlier we had noticed similar caterpillars on stagger-bush blueberry (Lyonia mariana). This would suggest Datana ranaeceps (post-burn datana) but the images in my only field guide, Caterpillars of Eastern North America by David L. Wagner, seem to better match Datana perspicua (spotted datana).