Woolly bear (Zoöl.), the hairy larva of several species of bombycid moths. The most common species in the United States are the salt-marsh caterpillar (see under Salt), the black and red woolly bear, or larva of the Isabella moth (see Illust., under Isabella Moth), and the yellow woolly bear, or larva of the American ermine moth (Spilosoma Virginica). -- Woolly butt (Bot.), an Australian tree (Eucalyptus longifolia), so named because of its fibrous bark. -- Woolly louse (Zoöl.), a plant louse (Schizoneura, or Erisoma, lanigera) which is often very injurious to the apple tree. It is covered with a dense coat of white filaments somewhat resembling fine wool or cotton. In exists in two forms, one of which infests the roots, the other the branches. See Illust. under Blight. -- Woolly macaco (Zoöl.), the mongoose lemur. -- Woolly maki (Zoöl.), a long-tailed lemur (Indris laniger) native of Madagascar, having fur somewhat like wool; -- called also avahi, and woolly lemur. -- Woolly monkey (Zoöl.), any South American monkey of the genus Lagothrix, as the caparro. -- Woolly rhinoceros (Paleon.), an extinct rhinoceros (Rhinoceros tichorhinus) which inhabited the arctic regions, and was covered with a dense coat of woolly hair. It has been found frozen in the ice of Siberia, with the flesh and hair well preserved.