352 EXPLANATION OF PLATE. 



hatched from the eggs they arfe light in color and covered with whitish 

 hairs. In a few hours they assume a dark hue. They usually remain 

 on or near the egg-cluster until they change in color, and should the 

 weather be cold they sometimes remain for several days in a semi- 

 torpid condition upon the egg-cluster. If the temperature is favorable 

 they usually search for food before they are twenty-four hours old, 

 During the first few weeks of their existence they remain most of the 

 time on the leaves, feeding mainly on the under side. Their feeding 

 habits are so uncertain that no rule can be given which will apply to ffll 

 individuals, but before they are half-grown they generally begin to 

 manifest their gi'egarious instincts. At that time and for the rest 

 of their existence as caterjiilhirs they spend a large part of the day 

 clustered in sheltered situations, and feed principally at night, going up 

 the trees and out on the branches after dark and returning before day- 

 break. Where they are so abundant that the food supply is insufficient 

 they evince much restlessness, and feed in numbers during all hours of 

 the day and night. The}' may then be seen hastening to and fro, both 

 up and down the trees. Those which have fed sufficiently are at once 

 replaced by hungry new-comers, and the destruction of the foliage goes 

 on incessantly. 



At such times the trunks and lower branches of trees are covered 

 with a moving mass of caterpillars, hurrying throngs are passing and 

 rei^assing, and nearly every leaf or denuded stem bears up one or more 

 of the feeding insects. The rustling caused by their movements and 

 the continual dropping of excrements is plainly audible. On tall trees 

 the larger caterpillars appear to crawl to the higher limbs, and they 

 seem to prefer to feed well out toward the end of the branches. They do 

 not feed gregariously except when in great numbers; therefore they 

 seldom strip one branch, as do the larvre of the Euvanessa antiojm, but 

 scatter throughout the trees, eating a little from each leaf. Early in 

 the season, when they are small and few in numbers, their ravages are 

 scarcely noticed ; but as they grow larger and more numerous, their 

 inroads on the tree decrease the foliage area night by night, vmtil sud- 

 denly all the remaining leaves are eaten, and the tree is stripped in a 

 single night. 



Food Plants. 



The gypsy moth is known to destroy the foliage of nearly all native 

 and introduced trees and plants of economic importance. The list of 

 its food plants includes nearly all evergreen and deciduous trees, most 

 bushes, shrubs, vines and vegetables and it has been seen to eat grass 

 and grain. Wherever the caterpillars become numerous they move 

 slowly, devouring nearly every green leaf and bud as they go. They 

 feed during a much longer season than the canker worm or the tent 

 caterpillar. In the months of June. July and August, 1891, trees which 

 had been stripped early in the season and whose leaves had again put 

 out were again defoliated by these caterpillars and kept bare all sum- 

 mer ; therelbre not only was all prospect of a fruit harvest destroyed, 

 but many trees were killed by this continual defoliation. 



