BOMBYCIDS. 105 
state in the vicinity of New York City, Philadelphia and other 
places where its food plant, the alanthus, has been cultivated as a 
shade tree. It became so common in Philadelphia and Washington, 
D. C., at one time as to be a pest, and threatened the destruction of 
the trees; but the parasites and birds seem now able to cope with 
it and hold it in check. 
_ This insect is reared in Asiatic countries for its silk, which is 
said to be strong and very durable, but lacks the beauty of that 
produced by Bombyx mori. It was probably for its silk that it was 
introduced into this country, but that it has ever been successfully 
utilized here for the manufacture of fabrics I have yet to learn. 
The female lays two hundred to three hundred cream-colored eggs, 
and the young caterpillars are yellowish profusely adorned with 
black spots and tubercles. The mature caterpillar is three inches 
long, of a clear bluish-green color adorned with blue tubercles. The 
cocoon is similar in shape to that produced by the next species de- 
scribed, Attacus promethia, and is a little larger. 
In some parts of the country the insect is double-brooded, the 
second brood remaining in its cocoons during the winter months, 
coming out late in June. The moth is a fine large insect, expand- 
ing, in large specimens, four or five inches. The females are usually 
a good deal larger, with broader wings than their mates. 
Attacus promethia is a very abundant species throughout a large 
part of the United States and Canada, and is one of the first of the 
family with whose life history the amateur collector is likely to 
become acquainted. The female moth deposits her eggs in July on 
the twigs of the wild cherry, sassafras and button-bush, sometimes 
five or six together and at others twenty or thirty or more in a 
Larya of Attacus promethia. 
cluster; and toward the end of that month the minute caterpillars 
make their way out and mount to the top of the tree or bush, where 
they may be found feeding on the tender young leaves. When fully 
grown the caterpillar is one of the handsomest, being two inches 
long, half an inch thick, very smooth and plump, and of a lght 
bluish-green color. There are four cylindrical coral-red tubercles on 
