Source : Webster's Revised Unabridged Dictionary (1913)

   {Red underwing} (Zo["o]l.), any species of noctuid moths
      belonging to {Catacola} and allied genera. The numerous
      species are mostly large and handsomely colored. The under
      wings are commonly banded with bright red or orange.

   {Red water}, a disease in cattle, so called from an
      appearance like blood in the urine.

Source : WordNet®

red underwing
     n : moth having dull forewings and red-marked hind wings [syn: {Catocala
         nupta}]