THE LEPIDOPTERA 257 



down to the twig at each end, which soon hardens and glistens. Within 

 the eggs the larv® develop and are ready to hatch by winter, but remain 

 within^ the egg-shells until spring. They then leave the eggs and may 

 feed first on the material covering the eggs, but soon crawl together to 

 some near-by fork of the tree and there spin a web (Fig. 259) in which 

 to live. From this they go out during the day to feed, spinning a thread 



Fig. 259.— Tent of the Apple-tree Tent-caterpillar, about half natural size. {Original.) 



as they go, perhaps to aid them in finding their way back. As they grow 

 the tent or web is enlarged by the addition of outer layers and may be 

 nearly a foot long and seven or eight inches across before the larvae are 

 full-grown, the feeding period being about 6 weeks. 



Though at first very small, the larvae grow rapidly and when of full size 

 are about two inches long, black with a white stripe along the middle of 

 the back and a row of pale-blue spots on each side, with a velvety-black 

 spot in front of each blue one (Fig. 260). Fine yellowish hairs are also 



present. 



When about through feeding the caterpillars scatter and finally 

 spin rather large, quite thick, white cocoons in any protected places 



17 



