This cute little guy, a late-stage instar of the spicebush swallowtail butterfly (Papilio troilus), was hiding inside a folded leaf of a spicebush (Lindera benzoin) along Turkey Trot trail on September 2nd.
The “eye spots” are actually on the thorax of the caterpillar and function as a predator deterrent. Masters of mimicry, the larva hide in the folds of leaves during the day, coming out at night to feed. The early stage instars are colored to look like bird droppings. As the larva grows, the “eye spots” that look like snake eyes become more prevalent. When the larva gets ready to pupate it does so on the underside of a suitable leaf fairly close to the ground where it transforms into what looks like a dead leaf.
For a look at great photos of the entire metamorphosis check out Field Notes from the Beiser Field Station.