gypsy moth

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A Eurasian moth (Lymantria dispar) whose caterpillars feed on foliage and are destructive to trees and shrubs especially in the northeast United States. It was introduced into the United States in the late 1800s.
• noun Informal A Republican in the US House of Representatives, representing a northeast or midwestern urban area, who sometimes supports moderate legislation and causes.

from the GNU version of the Collaborative International Dictionary of English.

• A tussock moth (Lymantria dispar or Porthetria dispar or Ocneria dispar) native of the Old World, but accidentally introduced into eastern Massachusetts about 1869, where its caterpillars have done great damage to fruit, shade, and forest trees of many kinds. The male gypsy moth is yellowish brown, the female white, and larger than the male. In both sexes the wings are marked by dark lines and a dark lunule. The caterpillars, when full-grown, have a grayish mottled appearance, with blue tubercles on the anterior and red tubercles on the posterior part of the body, all giving rise to long yellow and black hairs. They usually pupate in July and the moth appears in August. The eggs are laid on tree trunks, rocks, etc., and hatch in the spring.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Lymantria dispar, a species of moth.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun European moth introduced into North America; a serious pest of shade trees