Below are her notes, and a link she found to a wonderful photo portrait of all the different shapes a spicebush swallowtail takes as it grows towards adulthood. Thanks to Brownlee for sending the photo and info.
07/16/09 Spicebush Swallowtail caterpillar on front door of house within a couple of weeks after setting a Spicebush 15 feet from the door. How the 'pillar got there, past 10 feet of boxwoods, over five feet of brick paving, and a foot or two up the door, is a mystery. It was a striking sight, with the sun bringing out its bright yellow against the dark green of the door. In this picture the pale background and some shadow dulls the bright yellow.
Here's a website with many photos and more info.http://www.