Okay, as if a poo-brella isn't icky enough, this larva also appears to have some sort of tiny worm thing on it. I didn't notice it when I was taking the photos, but in looking at the photos I can see that the thing changes position. It's not part of the larva, is it? Is it a parasite?

Based on prior findings of adult tortoise beetles on this particular morning glory vine, I'm assuming this larva is a Mottled Tortoise Beetle.