These bright caterpillars are living in a pot of parsley. The pot has a 14" diameter, the parsley was over-seeded so it has formed a large head of parsley, maybe about 30" in diameter and there are at least 15 caterpillars. We would like to know what kind they are, and what we need to do to help them turn into butterflies.
I think it's one of the black swallowtail caterpillars.
This is indeed a larva of a black swallowtail, Papilio polyxenes - see http://tinyurl.com/65hux2
