THE GLAUCOPIDIANS. 337 



very rarely observed, in this vicinity. The caterpillars 

 are gregarious, that is, considerable numbers of them live 

 and feed together, collected side by side on the same leaf, 

 and only disperse when they are about to make their co- 

 coons. They are of a yellow color, with a transverse 

 row of black velvety tufts on each ring, and a few con- 

 spicuous hairs on each extremity of the body. They are 

 hatched from eggs, which are laid in clusters of twenty or 

 more together on the lower sides of the leaves of the grape- 

 vine and creeper ; and they come to their growth from the 

 middle to the end of August. They then measure six tenths 

 or rather more than one half of an inch in length. Their 



O 



feet are sixteen in number, and rather short, and their mo- 

 tions are sluggish. When touched, they curl their bodies 

 sidewise and fall to the ground, or, more rarely, hang sus- 

 pended from the leaves by a silken thread. When young, 

 they eat only portions of the surface of the leaf; but as they 

 grow older, they devour all but the stalk and principal veins, 

 and, passing from leaf to leaf, thus strip whole branches of 

 their foliage. When numerous, they do much damage to 

 the vines and fruit, by stripping off the leaves in midsum- 

 mer, when most needed. I' have found them in Massachu- 

 setts on the grape-vine and on the common creeper, or Ampe- 

 lopsis quinquefolia, and conjecture that the latter constitutes 

 their natural food. 



About the year 1830, Professor Hentz found them in 

 swarms upon cultivated grape-vines at Chapel Hill, in North 

 Carolina ; and constant care was required 'to check their 

 ravages there, during several successive years. Several 

 broods appeared there in the course of the summer ; but 

 hitherto, only one annual brood has been observed in 

 Massachusetts, although two or more broods may occasion- 

 ally be produced. When about to make their cocoons, 

 the caterpillars leave the vines, and retire to some sheltered 

 spot. They then enclose themselves, each in a very thin, 

 but tough, oblong oval cocoon, and soon afterwards are 

 43 



