Geographic location of the bug: Gettysburg, PA
Time: 06:08 PM EDT
Your letter to the bugman: What is this. Just found it on my parsley plant.
How you want your letter signed: Tina
This is a Black Swallowtail Caterpillar, and some common names are “Dill Worm, Parsley Worm, Celery Worm, Carrot Worm, Fennel Worm” according to BugGuide, because “The common names for the caterpillars vary because they can be found on many important cultivated plants in the Carrot Family. Pick the host plant, add the word ‘worm’, and you have another common name that has probably been used and published somewhere.”