Palmerworm \Palm"er*worm`\, n. (Zo["o]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 moths,
which destroys the foliage of fruit and forest trees,
esp. the larva of {Ypsolophus pometellus}, which
sometimes appears in vast numbers.