Looking a little more closely at the little guys, and doing some quick Google searching, I found out that they are most likely Eastern Black Swallowtail caterpillars. Some gardeners might be upset that their parsley crop was destroyed. But since I really don't use much parsley in my cooking, and I love butterflies, I couldn't be happier with my garden visitors.
I couldn't believe how many caterpillars were in the little container. I counted a total of eight! How many can you count in this picture (some of the additional ones I counted are hiding under some leaves).
This makes me want to plant even more parsley next year so that these little guys have even more to munch on! I can't wait to see the caterpillars turn into beautiful butterflies later this year.