The caterpillar of this beautiful butterfly is living here on Xanthoxylum carolinianum, or Prickly Ash; at least, till now I did not find it on any other plants. It can be found three times in a year, first in April and May, then in July, and again in September and October. If the caterpillars be touched, they stretch forth the reddish–brown fleshy fork from the neck, like all those of the genus Papilio. When they do not eat they are sitting rigid regularly on the surface of the leaves. It is most interesting that in this situation their appearance resembles very much the excrements of birds, on account of their color, consisting of white, gray and brown spots. This resemblance is considerably increased in the earlier stage of the larvae, which are particularly found on open places, and are thus very easily seen.