120 Btll/LETIN 76 



the last molt, the insects are very sociably inclined, not only seeking each 

 other when at rest, but feeding in company as well. 



In this state the full growth is attained by the caterpillars by the 

 middle or last of June or in about six weeks from the time of hatching. 

 This period is not however invariable, for those larvse that come out of 

 the eggs very.early do not develop as rapidly as those that come out when 

 food is more easily obtained and abundant and the weather is more favor- 

 able. 



While the forest caterpillars may feed at any time, by far the larger 

 part of their eating is done at night or during cloudy days. Weed' notices 

 that " the caterpillars commonly eat through the leaf in such a way that 

 the outer end drops to the ground." This is shown in the lower leaf in 

 figure 2. This is especially true when they are feeding in groves or where 

 trees are near together. It is the continual dropping of the bits of leaves 

 as well as of the excrement of the caterpillars that causes the sound like 

 pattering of rain which is often heard where the insects are numerous. 



When the caterpillars have ceased to feed, they soon lose their social 

 disposition and, no longer collecting in large masses, they wander nervously 

 hither and thither, leaving the trees where they have up to this 

 time contentedly fed and appearing about houses, sidewalks, fences, etc. 

 After several days of this wandering each selects a place in which to spin 

 its cocoon and then its journeyings are at an end. 



FOO0 OF THE CATERPILLAR 



Like most insects, and all moths, this species does no injury except in 

 the larva, or caterpillar state. Weed' gives a list of between thirty and 

 forty trees and shrubs the leaves of which the caterpillars are known to eat, 

 but this list might as well be increased until it includes nearly all the trees 

 growing in any given locality, for there are few that they do not attack 

 at one time or another. Some kinds of trees however, are much more to 

 the taste of the caterpillars than others. In this and adjoining states, 

 during the last few years the maples have suffered far more from their 

 ravages than any other trees. So much has this been the case that 

 in many places the insect is known by the name of maple worm. In 

 other states, however, the oaks have been most attacked, elsewhere the 

 blue gums or poplars and sometimes apple trees are preferred. In some 

 groves of various species of trees which were attacked last year all were 

 defoliated alike. Still it is as an enemy of the sugar maple that it has at- 

 tracted most attention in Vermont. 



1 N. H. Sta. Bui. 64, pp 83-84 (1899). 



2 Loc^cit., pp 86-87. 



