Wed, Oct 8, 2008 at 6:21 PM
Today, I found this caterpillar on my driveway underneath a Hickory tree. It is about 1 1/2 inches long, light brown, purple dots and two, yellow, “eye-like” dots on its body behind its head. When I carefully picked it up, I must have startled it and a strange yellow, forked tongue(?) came to its defense along with a strange odor. I’ve seen many insect defense mechanisms but none quite like this. Anyway, I live in Sussex County, New Jersey (northwest) and have never seen a caterpillar like this. Looking at your photos it appears to be a swallowtail of some type. Can you identify for sure? Thanks!
Northwest NJ, Sussex County
This is most likely an Eastern Tiger Swallowtail Caterpillar, but you are also within the range of the Canadian Tiger Swallowtail. This typically green caterpillar changes color to brown or occasionally orange just before pupation. The scent gland you mentioned is characteristic of the swallowtails and is known as the osmetrium.