\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.