webworm(n = noun.animal) - several gregarious moth larvae that spin webs over foliage on which they feed;
is a kind of caterpillar
is a member of family lasiocampidae, lasiocampidae
has particulars: fall webworm, hyphantria cunea, garden webworm, loxostege similalis

   Any one of various species of moths whose gregarious larvæ eat the leaves of trees, and construct a large web to which they retreat when not feeding. [1913 Webster]
" The most destructive webworms belong to the family Bombycidæ, as the fall webworm (Hyphantria textor), which feeds on various fruit and forest trees, and the common tent caterpillar, which feeds on various fruit trees (see Tent caterpillar, under Tent.) The grapevine webworm is the larva of a geometrid moth (see Vine inchworm, under Vine)." [1913 Webster]

fall webworm, garden webworm, webworm moth