ORDER IV.—MOTHS AND BUTTERFLIES. 159 
much heavier than those of the Silk-worm, and will yield a 
greater quantity of silk; and as the insects remain un- 
changed in the chrysalis state from September to June, the 
cocoons may be kept for unwinding at any leisure time 
during the winter. The Luna, Polypheme, Cecropia, and 
Promethea Moths are the only native insects belonging to 
the genus Atiagus known to me. ‘Their large cocoons, con- 
sisting entirely of silk, the fibres of which far surpass those 
of the Silk-worm in strength, might be employed in the 
formation of fabrics similar to those manufactured in India 
from the cocoons of the Tusseh and Arindi Silk-worms, the 
durability of which is such that a garment of Tusseh-silk 
is scarcely worn out in the lifetime of one person, but often 
descends from mother to daughter; and even the covers of 
palanquins made of it, though exposed to the influence of 
the weather, last many years. Experiments have been 
made with the silk of the Cecropia, which has been carded 
and spun, and woven into stockings that wash like linen.” 
With all these facts before us, however, the raising of 
Silk-worms for the production of silk in this country has 
never yet been a flourishing branch of industry, nor are we 
able to foresee the time when it will become so. 
Another large silk-producing Moth is the PotypuEemMe 
Morn (Attacus Polyphemus), Fig. 35. Its name, derived 
from one of the giants of mythology, Linnzus gave to this 
Moth probably on account of the large-size of its wings, 
which, like those of the Cecropia, expand from three to six 
inches. ‘They are of an ochre-yellow color, clouded with 
black, and each wing is ornamented with a transparent spot 
resembling an eye. The caterpillar of this Moth is found 
in July or August, according to the geographical latitude, 
on oak, elm, and lime trees, and is from two to three inches 
long, and nearly as thick as a man’s thumb. Its body is 
pale, bluish green, covered with orange-colored and purple 
warts. Its head and feet are black. When full crown, it 
