280 INSECTS INJURIOUS TO VEGETATION. 



spinning its cocoon, early in September, on the twigs of the trees 

 or bushes on which it Hves. The cocoon is fastened longitudi- 

 nally to the side of a twig. It is, on an average, three inches 

 long, and one inch in diameter at the widest part. Its shape is an 

 oblong oval, pointed at the upper end. It is double, the outer 

 coat being wrinkled, and resembling strong brown paper in color 

 and thickness ; when this tough outer coat is cut open, the inside 

 will be seen to be lined with a quantity of loose yellow-brown 

 strong silk, surrounding an inner oval cocoon, composed of the 

 same kind of silk, and closely woven hke that of the silk-worm. 

 The insect remains in the chrysahs form through the winter. 

 The moth, which comes forth in the following summer, would not 

 be able to pierce the inner cocoon, were it not for the fluid pro- 

 vided for the purpose of softening the threads ; but it easily forces 

 its way through the outer cocoon at the small end, which is more 

 loosely woven than elsewhere, and the threads of which converge 

 again, by their own elasticity, so as almost entirely to close the 

 opening after the insect has escaped. 



A few brown and curled leaves may frequently be seen hanging 

 upon sassafras-^trees during the winter, when all the other leaves 

 have fallen off. If one of these leaves is examined, it will be 

 found to be retained by a quantity of silken thread, which is 

 wound or woolded round the twig to the distance of half an inch 

 or more on each side of the leaf-stalk, and is thence carried down- 

 wards around the stalk to an oval cocoon, that is wrapped up by 

 the sides of the leaf. The cocoon itself is about ^n inch long, of 

 a regular oval shape, and is double, hke that of the Cecropia 

 caterpillar, but the outer coat is not loose and wrinkled, and the 

 space between the outer and inner coats is small and does not 

 contain much floss silk. So strong is the coating of silk that sur- 

 rounds the leaf-stalk, and connects the cocoon with the branch, 

 that it cannot be severed without great force ; and consequently 

 the chrysalis swings securely within its leaf-covered hammock 

 through all the storms of winter. Cocoons of the same kind are 

 sometimes found suspended to the twigs of the wild cherry-tree, 

 the Azalea, or swamp-pink, and the Cephalanthus, or button- 

 bush, but not so often as on the sassafras-tree. Two of them, 

 hanging close together on one twig, were once brought to me, 



