If the deck were not on the second story, I would assume it were the dang blasted %*##?! deer who eat everything to the point that I only try growing plants on our deck.
Here is what I found.
Notice the stems in the top of the photo. Once I figured out the dang blasted deer had not climbed up the deck steps to strip my parsley I knew what it had to be: a caterpillar- specifically for the Black Swallowtail butterfly.
Here is a close up:
Isn't h/she beautiful? It is nearing maturity when it reaches this color. Love the stripes and the yellow dots are just too much! But the plant is unlike to keep this one going until it is time for it to become a pupa. I am going to buy some parsley tomorrow.