128 NETTLE TORTOISE-SHELL BUTTERFLY. 



The eggs of this insect are covered with a moist, 

 glutinous substance, by means of which they adhere 

 firmly to the plants on which they are deposited. 

 About the middle of May, the young caterpillars 

 emerge from this envelope, and may be observed, of 

 a light green colour, congregated and moving about 

 on the tops of the nettles, under a web of exquisitely 

 fine fibres, which covers the whole tops of the plant, 

 and is taken for a spider's web to which it has a 

 strong resemblance by those unacquainted with the 

 history of insects. It is not long before they cast 

 their first skin, at which time they shift to a fresh 

 part of the plant, and leave behind them their old 

 covering, adhering to the web. On acquiring their 

 third skin, they again change place, but still keep 

 under the protection of their web. In this change 

 they become black ; after which they quickly increase 

 in bulk, and are soon so large, that the community 

 are forced to separate into distinct companies. They 

 undergo, altogether, six changes of skin while in the 

 caterpillar state, in the last of which they become 

 solitary, living a retired life, quite remote from each 

 other ; and, in this condition, they make such ravages 

 among the nettles, that nothing remains on the plants 

 to which they attach themselves but the fibres of the 

 leaves and stalks. These caterpillars are frequently 

 so numerous, and so thickly studded on the plants, as 

 to give them the appearance of being covered with 

 black velvet. 



The larvae of the Nettle Tortoise-shell Butterfly 

 arrive at their full size about the beginning of June, 



