As larvae, just prior to the long sleep where it turns into a butterfly. It is still crawling and eating at this point. They chew so loud you can hear them crunching on the crisp leaves.
Caterpillars, I saw these the first year: http://www.pbase.com/rcm1840/lifecycleofblsw
and these this year: https://willowhousechronicles.files.wordpress.com/2010/07/caterpiller1.jpg
Those are riveting pictures, all of them! In the last one, StoneSoup, are those parsley stems?
Those aren’t my pics, btw, just some I hunted up to show what had visited me. I think the needled one is dill, maybe fennel.
Interesting. Nothing in my herb garden (flat parsley, oregano, dill, sage, rosemary, basil) gets eaten except the curly parsley. Maybe my region doesn’t have those other butterflies?
Here are range maps for the black swallowtail. https://www.google.com/search?q=black+swallowtail+range+in+U.S.&rlz=1C1CHWA_enUS543US543&espv=2&biw=1920&bih=955&tbm=isch&tbo=u&source=univ&sa=X&ved=0CCkQsARqFQoTCNb5worm3sgCFYKaHgodGT4MEw
Nothing else gets eaten here; I grow apple mint, oregano, basil, rosemary, thyme and sometimes sage on the patio. I planted dill in the pollinator garden near the parsley, which is now sprouting all over my property. I also got my first ever hummingbird, SUCCESS! My grudge against them for never visiting me launched an all out assault on their senses, and I got one my first year, in September.