fall webworm

from the GNU version of the Collaborative International Dictionary of English.

• noun (Zoöl.) The larva of any moth of the genus Hyphantria, which spins a web around the foliage on which it feeds.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Hyphantria cunea, a moth in the family Arctiidae known principally for its larval stage, which creates characteristic webbed nests on a wide variety of hardwood trees in the late summer and fall.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a variety of webworm