from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Any of several caterpillars that injure fruit trees by feeding on their leaves, especially the small green caterpillar of the North American moth Dichomeris ligulella.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A gelechiid moth, Dichomeris ligulella, destructive to certain trees.
from the GNU version of the Collaborative International Dictionary of English
- n. 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.
- n. 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.
from The Century Dictionary and Cyclopedia
- n. A caterpillar; especially, a hairy caterpillar injurious to vegetation, but what kind is unknown or undetermined.
- n. In the United States, the larva of the tineid moth Ypsilophus pometella, which in eastern parts of the country appears on the leaves of the apple in June, draws them together, and skeletonizes them.
From the way they suddenly appear in large numbers like a throng of pilgrims.(American Heritage® Dictionary of the English Language, Fourth Edition)
palmer + worm, because wandering about like a palmer. (Wiktionary)