Tiny caterpillar. TINY caterpillar.

[urbpan]

It wasn't until I posted this pic on Facebook (begging the author of this book for ID help) that I realized the caterpillar is in the picture. The animal that made this beautiful S curve is at the bottom of it, camouflaged by color and body shape. It's an almost imperceptibly small caterpillar. I verified this yesterday by going out to the little tree and finding more caterpillars, now fatter and larger from nine additional days of eating. I also assumed that the little tree was a chokecherry, but I was coached to properly identify it as a black cherry. So much to learn.

EDITED TO ADD:
SO much to learn. This "caterpillar" is very likely a sawfly larva, which is to say, not a caterpillar at all. Stay tuned.