Any of various caterpillars, of diverse moth families, that spin a web; the moth species of such a caterpillar.

plural of webworm

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.

plural of fall webworm

Any moth whose larvae inhabit web-like structures.