INSUCT NOTES. 211 



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

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

 silken web, are varied in shape, those upon oak trees for instance 

 being differently formed from those upon wild cherry, in accord- 

 ance with the difference in the size and pliability of the leaves. 

 They vary too, more or less, upon the same tree, in the number 

 of attachments to the twig and somewhat in size. However, 

 this variety in size and shape serves as a distinctive mark, as it 

 distinguishes nests of the brown tail moth from the uniform 

 and regular shaped cocoons of other moths found often upon 

 orchard trees in winter. 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 with tiny 

 living caterpillars it is the winter nest of the brown-tail moth. 

 Two types of the winter nests are shown in Figs. 17 and 18. 



The caterpillars in the spring. 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, completely stripping the trees where 

 they are numerous. Orchard trees are especially susceptible, 

 but oak, elm, and many other shade and forest trees are often 

 ruinously attacked. 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 conspicuous 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 abdom- 

 inal 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 people are 

 likely to escape, as the caterpillars drop from the branches and 

 creep about, even entering houses. Direct contact with the 

 insects themselves is not necessary however, for when the cater- 



