Spotting

Description:

I think these are two moths (mating - there's a head on each end; the insect facing up is many times larger than the mate).

Notes:

I was walking on a section of Northwestern's Evanston campus near Lake Michigan. The day before, a fast-moving line of thunderstorms knocked over hundreds of trees, including a very large willow tree. The bugs are perched on a sawed off branch. It was probably about 6:30 p.m., ~80 degrees, humid. I actually stopped to photograph the larger bug when her (his?) mate flew in. It was really pretty remarkable. Does anyone know who these guys are? Thanks!