I think I had better tell this one backwards: While we were out of town last mid-September, our friends babysat our 2 cocoons for us here in Atlanta, Georgia, and to everyone’s amazement, hatched an Ichneumon. They took a picture for us, which I’m afraid I don’t have. However, we checked our bug book, as well as your fabulous site, and are quite sure that’s what it was. Only one of the two cocoons hatched. We had thought (very wrongly) that the caterpillars were monarchs. They were striped, but later we realized that the stripe colors were slightly wrong. They were happily eating parsley (beginning where we found them at a plant nursery), which should have been our first clue that these weren’t really monarch caterpillars. Well, they ate and ate until at last they both curled upside down one evening. The next morning, we had two very strange looking cocoons, as you can see in the pictures I’ve attached. They were not hanging down, but propped right-side up, and leaning back against a thread of silk, with it’s ends attached to the twig like… struts? I think you can make it out in at least one picture (13cocoonsB.jpg). The cocoon that hatched has a hole in it. I am not up for cutting open the second one, but could perhaps be convinced if necessary. So, what in the heck were these things (before they were devoured by the Ichneumon)? I wasn’t able to match the caterpillars to anything in my bug book, or on your site. It didn’t occur to me to photograph them until it was too late. I hope the cocoon photos are enough of a clue! Thanks … we love your site!
in Atlanta, GA
First, your cocoons are not cocoons, which is the word that describes the silken coating spun by most moth caterpillars to cover the pupa. Your butterfly pupa is also called a crysalis. The silken thread and the upward orientation is a dead giveaway that it is one of the genus Papilio, the Swallowtails. The food plant, parsley as well as the striped color would tend to identify the Black Swallowtail, Papilio asterius, as the most likely suspect.