ORDER IV. MOTHS AND BUTTERFLIES. 131 



cellcnt silk, and of which extensive use will probably be 

 made as soon as the young giant of North America arrives 

 at maturcr age. Of these I shall speak at length in some 

 of the following pages. 



Various kinds of apparatus have been invented for the 

 purpose of raising caterpillars, and the simplest kind are 

 boxes, the bottom of which is covered with earth, and the 

 top with gauze, so as to admit of fresh air at all times. In 

 some places large cages, like those for birds, are used, 

 which arc also covered with gauze, and in which are placed 

 the different plants upon which the caterpillars feed. This 

 is a very convenient contrivance for observing their mode 

 of living, the casting of their skins, and their metamorph- 

 oses, as also for obtaining handsome and perfect specimens 

 for the cabinet. They may be raised, however, in the same 

 manner as silk-worms are generally raised, and which we 

 shall presently describe. 



As soon as the cold of autumn deprives the trees and 

 shrubs of their foliage all caterpillars disappear, either 

 metamorphosing themselves into cocoons, or, if not yet 

 ready for such a change, concealing themselves under the 

 ground. In the following spring, as soon as the new leaves 

 appear on the trees, they come out from their caverns in the 

 hollow trees or the crevices of the rocks, and with a host of 

 new ones that issue from the eggs which were deposited in 

 the previous autumn, they commence their ravages, devour- 

 ing all the new leaves and shoots within their reach. 



After the caterpillars have cast their skin several times 

 and are full grown, they metamorphose themselves into an 

 immovable cocoon (chrysalis, aurelia, pvpa), which eats no 

 more, and under the horny skin of which may almost al- 

 ways be recognized the wings and other members of the 

 future Butterfly or Moth. Many of these come out after a 

 few weeks, during the summer, again lay their eggs, from 

 which proceed other caterpillars, which latter generally 



