Observed at visitor center of Big Thicket National Preserve near Kountze TX by Mary Kay.
She noticed the leaves had been completely stripped from the upper third or so of a Yaupon holly (Ilex vomitoria).
See gcwarbler's observation of the same caterpillar: http://www.inaturalist.org/observations/4374809
Note to myself: I know that horn color is a key in the ID of these caterpillars but neglected to observe.... :-(