About the Red Underwing
The red underwing (Catocala nupta) is a moth of the family Erebidae. The species was first described by Carl Linnaeus in his 1767 12th edition of Systema Naturae. This is a large (80 mm wingspan) nocturnal Palearctic (including Europe) species which, like most noctuids, is above and with the wings closed drably coloured to aid concealment during the day. It flies in August and September, and comes freely to both light and sugar.
C. nupta L. Forewing pale grey powdered with darker grey, sometimes with dark grey banded suffusion, and in some cases yellowish-tinged; sometimes the cellspace before reniform coalescent with the spot below reniform, and a space along outer line, before it above middle and beyond it below, are all whitish: inner and outer lines double, black and grey; the outer line less oblique below middle and forming two more conspicuous angles on each side of vein 2, the lower one double, then deeply indented along vein 1 median shade generally clear and produced squarely outwards beyond the reniform, which has a thick black central lunule, a curved black inner edge, and a tridentate outer one; subterminal line pale and dark grey... Wikipedia →