Isabelle found two of these feeding on the Rue plants in the Backyard Garden area of the FWG, and showed them to Sandy who showed them to me. Wonderful to see them. And amazing how those rue plants attract butterflies such as this species and the giant swallowtail, to lay eggs on it. There is a 3rd, early instar caterpillar with these two which may be a giant swallowtail or may be this species. Need to wait until it gets a bit bigger.