Papilio Polyxenes
Black or American Swallowtail butterfly
Actually not a butterfly at this point but just a healthy looking caterpillar.
It turns out parsley, carrot and dill are among the favorite foods of these and more than likely this fellow hatched from an egg laid in the parsley thicket a couple feet away. Apparently the small exposed dill volunteer was tempting enough to entice leaving the relative safety provided by the thick cover of parley.
He has already nubbed off one stem to the right….
A closer view; if you click through the picture twice and fully enlarge it you can really see the difference in the fuzzy middle legs/feet and the clawed rear ones. (That is if you are bug-geeky enough to care…)
More via wiki, including nice photos of “the finished product”: The (eastern) black swallowtail (Papilio polyxenes), also called the American swallowtail or parsnip swallowtail
I’ve got herbs to spare for these guys, so they will be left to eat as they wish.
Behind cohutt's fence 
That is a good-looking bug. What beautiful colors!
It’s nice when we can leave some or share some with the critters
Cabbage worms won’t be treated so benevolently though, i can assure you. I Went back out and this little guy was diligently working on the same plant 24 hours later. He isn’t as revenous as some seem to be.