Palmerworm
Pronunciation : Palm"er*worm`, n. (Zo?l.) (a) Any hairy caterpillar which appears in great numbers, devouring herbage, and wandering about like a palmer. The name is applied also to other voracious insects. Joel. i. 4. (b) In America, the larva of any one of several moth
Part of Speech : which
Definition :
sometimes appears in vast numbers.
Source : Webster's Unabridged Dictionary, 1913