Banded tussock moth (Halysidota tessellaris) caterpillar with stemmata peeking out from behind the anterior tufts. The second photograph shows the barbed setae, which will eventually be detached and rewoven into the cocoon.
This is a newly-molted variable oakleaf caterpillar (Lochmaeus manteo), with old head capsule still attached. I initially thought the capsule was the head and that the thorax had eyespots, but John and Jane Balaban on Bugguide.net pointed out the obvious to me.
This species sprays formic acid, apparently.
FYI, Al Denelsbeck posted an almost identical image here, complete with close-up of the eyes.
Sycamore tussock moth (Halysidota harrisii) caterpillar at Hildacy Farm Preserve in Media, PA. I remember these as a child mainly because of their urticating hairs. But they are also really, really cute. I especially like the white ones because their orange tufts stand out better than on the yellow variety. Don’t you just want to pick it up?? If by chance you don’t know what “urticating” means, I highly recommend the experience. You won’t forget.