Palmerworm \Palm"er*worm`\, n. (Zool.)
(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.
[1913 Webster]