IHE FALL WEB-WORM. 
357 
rare ; and it appears here in July and August. It closely 
resembles the ruby tiger-moth, Arctia fidiginosa^ of Europe, 
the wings of which are not so transparent, and have two 
black dots on each of them, with a distinct row of larger 
black spots around the outer margin of the hind pair. The 
caterpillar of our moth is unknown to me ; it will probably 
be found to resemble that of the ruby tiger, which is black¬ 
ish, and thickly covered with reddish-brown or reddish-gray 
hairs. It eats the leaves of plantain, dock, and of various 
other herbaceous plants, grows to the length of one inch and 
three eighths, passes the winter concealed beneath stones, or 
in the crevices of walls, and makes its cocoon in the spring. 
The caterpillars of all the foregoing Arctians live almost 
entirely upon herbaceous plants ; those which follow (with 
one exception only) devour the leaves of trees. Of the latter, 
the most common and destructive are the little catei’pillars 
known by the name of fall web-worms, whose large webs, 
sometimes extending over entire branches with their leaves, 
may be seen on our native elms, and also on apple and other 
fruit trees, in the latter part of summer. The eggs, from 
which these caterpillars proceed, are laid by the parent moth, 
in a cluster upon a leaf near the extremity of a branch; they 
are hatched from the last of June till the middle of August, 
some broods being early and others late, and the young cat¬ 
erpillars immediately begin to provide a shelter for them¬ 
selves by covering the upper side of the leaf with a web, 
which is the result of the united labors of the whole brood. 
They feed in company beneath this web, devouring only the 
upper skin and pulpy portion of the leaf, leaving the veins 
and lower skin of the leaf untouched. As they increase in 
size they enlarge their web, canwing it over the next lower 
leaves, all the upper and pulpy parts of which are eaten in 
the same way, and thus they continue to work downwards, 
till finally the web covers a large portion of the branch with 
its dry, brown, and filmy foliage, reduced to this unseemly 
condition by these little spoilers. These caterpillars (Plate 
