Two caterpillars

Yesterday my wife found a caterpillar on a white oak that she was pruning. A search of Wagner's tomes on caterpillars provided an ID: Acronicta americana, American Dagger Moth. Here's the photo:
Later in the day, while digging up a black locust that had to go, I found two caterpillars on the ground and saved one for a photo. Consulting Wagner's tomes showed it to be Euparthenos nubilis, Locust Underwing Moth. Here's the photo: