234 INSECTS IXJUmOUS TO VEGETATION. 



measure about one inch and a half in length. Being of a pale 

 green color, they are not readily distinguished from the ribs of 

 the leaves beneath which they live. They do not devour the 

 leaf at its edge, but begin indiscriminately upon any part of 

 its under side, through which they eat irregular holes. When 

 they have completed the feeding stage, they quit the plants, 

 and retire beneath palings, or the edges of stones, or into the 

 interstices of walls, where they spin a little tuft of silk, entangle 

 the hooks of their hindmost feet in it, and then proceed to form 

 a loop to sustain the fore part of the body in a horizontal or 

 vertical position. Bending its head on one side, the caterpillar 

 fastens to the surface, beneath the middle of its body, a silken 

 thread, which it carries across its back and secures on the 

 other side, and repeats this operation till the united threads 

 have formed a band or loop of sufficient strength. On the 

 next day it casts off the caterpillar skin, and becomes a chry- 

 salis. This is sometimes of a pale green, and sometimes of a 

 white color, regularly, and finely dotted with black ; the sides 

 of the body are angular, the head is surmounted by a conical 

 tubercle, and over the fore part of the body, corresponding to 

 the thorax of the included butterfly, is a thin projection, having 

 in profile some resemblance to a Roman nose. The chrysalis 

 state lasts eleven days, at the expiration of which the insect 

 comes forth a butterfly. The wings are white, but dusky next 

 to the body ; the tips of the upper ones are yellowish beneath, 

 with dusky veins ; the under side of the hinder wings is straw- 

 colored, with broad dusky veins, and the angles next to the 

 body are deep yellow ; the back is black, and the antennae are 

 blackish, with narrow white rings, and ochre-yellow at the tips. 

 The wings expand about two inches. I have seen these but- 

 terflies in great abundance during the latter part of July, and 

 the beginning of August, in pairs, or laying their eggs for a 

 second brood of caterpillars. The chrysalids produced from 

 this autumnal brood survive the winter, and the butterflies are 

 not disclosed from them till May or June. In gardens or 

 fields infested by the caterpillars, boards, placed horizontally 

 an inch or two above the surface of the soil, will be resorted 

 to by them when they are about to change to chrysalids, and 



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