I am not sure is swallowtail larvae take time to color up or if they hatch as little versions of the fatsos I love to see... but they are bright lime green with dramatic black and white stripes.
they do love dill and parsley. when I buy my annuals in flats each spring I always buy half a flat of parsley and plant it all over... I don't have good luck with dill, mine always goes to seed and dies, parsley just lasts longer and is easier to find in inexpensive 4-6 packs