The Collaborative International Dictionary of English v.0.48:

Nymphalis \Nymphalis\ prop. n.
   The type genus of the Nymphalidae, including the mourning
   cloak butterfly (Nymphalis antiopa).

   Syn: genus Nymphalis.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

Nymphalis
    n 1: type genus of the Nymphalidae: mourning cloak butterflies
         [syn: Nymphalis, genus Nymphalis]