The Collaborative International Dictionary of English v.0.48:

Isabella moth \Is`a*bel"la moth`\ (?; 115). (Zool.)
   A common American moth (Pyrrharctia isabella), of an
   isabella color. The larva, called woolly bear and hedgehog
   caterpillar, is densely covered with hairs, which are black
   at each end of the body, and red in the middle part.
   [1913 Webster]