290 MAINE AGRICULTURAL EXl'LRI.MLNT STATION. I906. 



The caterpillars are gregarious and feeding as they do, the 

 whole brood on a branch together, they strip off the leaves 

 thoroughly as they go. Unlike many caterpillars, they do not 

 eat their molted skins and these are frequently seen clinging 

 to a naked branch long after the caterpillars themselves have 

 disappeared. 



When full grown, the caterpillars usually migrate from the 

 tree on which they fed to some neighboring shelter. The} 

 suspend themselves from the eaves of buildings, edges of clap- 

 boards, fence-rails or similar places and there molt for the last 

 time the spiny skin. 



The insect now appears in the form of a peculiar ash gray 

 01 brownish chrysalis which is sure to excite curiosity the first 

 time it is met with. The shape is much more easily represented 

 by a figure than by a description. When disturbed the chrysalis 

 wriggles violently. Fig. 29. 



In about two weeks (usually less with this species), the skin 

 of the chrysalis cracks open and the adult butterfly emerges. 

 The butterflies of the first brood deposit eggs for the next 

 generation at once, but those of the fall brood hibernate in the 

 adult stage and deposit eggs in the spring. 



Natural Enemies. A disease sometimes attacks this insect 

 in the larval stage and a whole brood of limp caterpillars will 

 be found hanging dead to the branch where they had been 

 feeding. A Tachina fly is commonly parasitic upon the cater- 

 pillar, the full grown maggots dropping from the caterpillars to 

 the ground to pupate, about the time the caterpillars are 

 suspending themselves in preparation for the chrysalis stage. 

 Caterpillars thus attacked, however, die before the chrysalis 

 is formed. A minute hymenopterous parasite deposits eggs in 

 the chrysalis, as many as 89 developing in a single chrysalis. 



Remedies. In localities where this insect is troublesome, 

 it is well to be on the w^atch for the caterpillars and remove 

 them W'hile they are yet young. As they are gregarious, the 

 whole brood can be removed easily by clipping the branch on 

 which they are found. Removing the caterpillars by hand is 

 the only remedy needed for small trees and will be sufficient 

 for larger trees in towns supplied with apparatus for removing 

 the winter nests of the brown-tail moths. Where a treatment 

 by poison is desired, arsenical sprays should be thoroughly 

 applied. 



