MAINU AGRICUIvTURAI, EXPERIMENT STATION. I91O. 353 



egg cluster. When they have eaten all but the skeleton of the 

 first leaf, they draw another into the web and repeat the process 

 at intervals during the late summer. They feed slowly, how- 

 ever, and spend so much time spinning their web that they do 

 comparatively little damage to the trees in fall, and they are still 

 very small (about one-fourth of an inch in length) when cold 

 weather comes on. 



The ivintcr nests. — (Fig. 38). In the fall the young cater- 

 pillars weave additional layers of silk about their retreat, fas- 

 tening it securely to the branch by the web, and pass the winter 

 thus in colonies of one hundred and fifty to three hundred in a 

 single nest. This is a very unusual yet most commendable 

 habit in a caterpillar pest, for they can be killed, hundreds at a 

 time, simply by burning the nests in which the colonies hiber- 

 nate. The nests, composed of leaves, bound firmly together by 

 a silken web, are varied in shape. In spite of the superficial 

 variety the essential characteristics of the brown-tail moth nests 

 are soon learned, and even anyone unfamiliar with the nest can 

 make himself perfectly certain if he will cut carefully into the 

 nest. // the structure contains one or more silken cells filled 

 zvith tiny living caterpillars it is the winter nest of the brown- 

 tail moth. 



Early in the spring the young caterpillars emerge from their 

 winter nests and feed upon the opening leaf buds. Until about 

 the middle of June they feed greedily upon the leaves, com- 

 pletely stripping the trees where they are numerous. When 

 full grown the caterpillars are about one and one-half inches 

 long. They are dark brown with a sprinkling of orange. Long 

 fine reddish-brown hairs cover the body, and a row of conspic- 

 uous white hairs runs along each side. Like the caterpillars of 

 the tussock and gypsy moths, they bear bright red tubercles on 

 the top of the sixth and seventh abdominal segments. 



Poisonous qualities of the caterpillars. — Were the caterpillars 

 to be feared only for their ravages upon orchard and other 

 trees, the situation would be alarming enough, but not less 

 serious is the physical discomfort experienced by people living 

 in infested districts. When the minutely barbed hairs of the 

 caterpillar come in contact with the skin they cause an eruption 

 similar to and in many cases worse than ivy poisoning. These 

 hairs are brittle and where the caterpillars are numerous few 



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