THE FALL WEB-WORM. 357 



rare ; and it appears here in July and August. It closely 

 resembles the ruby tiger-moth, Arotia fuliginosa, 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 caterpillars 

 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. up6n 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, carrying 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 



