Pink underwing (Catocala concumbens) is a medium to large sized, strikingly colored, underwing moth. It is common from northeastern United States, west to the Upper Midwest, and north to Manitoba and Alberta. In Minnesota it is more common in the northern half of the state.
Pink underwing adults are 1¼″ to 1½″ in length and have a wingspan of 2⅜″ to 3″. The forewings are a nondescript, mottled gray and tan with a pale, kidney-shaped spot and two thin, jagged, black lines. The hindings are pink two black bands and a wide white fringe. They are active at night. When at rest the wings are folded roof-like over the body. When approached or disturbed they spread their forewings revealing the startling color of the hindwings, possibly to scare off or give it time to escape a predator.
There are 39 underwing moth species found in Minnesota, and most are similar in appearance. Pink underwing is distinguished by the pale colors and paler reniform spot on the forewings; and by the pink hindwings with a wide, straight, uninterrupted, white fringe.