Source : Webster's Revised Unabridged Dictionary (1913)

Silverspot \Sil"ver*spot`\, n. (Zo["o]l.)
   Any one of numerous species of butterflies of the genus
   {Argynnis} and allied genera, having silvery spots on the
   under side of the wings. See Illust. under {Aphrodite}.

Source : WordNet®

silverspot
     n : butterfly with silver spots on the underside of the hind
         wings