In spite of Dutch Elm Disease, we still have a number of American elm trees growing around. They grow to about a foot in diameter, maybe twenty five or thirty feet high, then they die.
I took this photo of a question mark, Polygonia interrogationis, when it seemed to be laying eggs on the underside of the American elm leaves. I did not look to see if there were eggs, however. 
Yesterday I found several caterpillars on the undersides of the leaves of the tree in question. Here is a photo of one. It looks like the question mark caterpillar to me.
The roused bear 