Took a walk yesterday and ended up at a small limestone outcrop over the river. In an area of about 10'x 10' I saw a moth fly up and land in plain view on the upper side of a leaf. Then I noticed another. There were 5 within view (only 4 in this photo), all on the upper sides of leaves of Motherwort, Leonurus cardiaca and Catnip, Nepeta cataria in the shade of a cluster of cedar trees. They just sat. One can only watch no-activity for a short while so I moved about 5 feet and saw more. Altogether I saw 15.

Last year I saw 2 (my first) at this same spot

June 14, 2015, update: saw 10 today, same spot, 3 at once. Would really like to find larvae feeding. On what?
June 18, 2015, saw 3
June 24, 2015, didn't see any