The mottled prominent (Macrurocampa marthesia) is found in the Notodontidae family and is a relatively common caterpillar found on oaks and other members of the Fagaceae. The long tail-like appendages are the anal prolegs and are quite long in early instars, becoming progressively shorter with each molt. Each of these animals were found in mid-late August at the Schoolcraft Prairie property in Washington County, Missouri.
A Thousand Acres of Silphiums 