This is an Ultronia Underwing, or Catocala ultronia. It is a medium sized underwing moth, with a wingspan of 4.6-6
centimeters. Note the difference between the moth with its wings closed, below, and with the hind wings showing, to the right.
These striking underwings are used to scare off would-be predators.
Ultonia underwings feed on apple and cherry trees.