LEPIDOPTERA. 249 



our sea-board, and now getting to be common in the interior of 

 the State, whither it has probably been introduced, while under 

 the chrysalis form, with the salt hay annually carried from the 

 coast by our inland farmers, closely resembles the yellow bear in 

 some of its varieties. The history of this insect forms the ^sub- 

 ject of a communication made by me to the " Agricultural So- 

 ciety of Massachusetts," in the year 1823, and printed in the 

 seventh volume of the " Massachusetts Agricultural Repository 

 and Journal," with figures representing the insect in its diflerent 

 stages. At various times and intervals since the beginning of the 

 •present century, and probably before it also, the salt marshes 

 about Boston have been overrun and laid waste by swarms of 

 caterpillars. These appear towards the end of June, and grow 

 rapidly from that time till the first of August. During this month 

 they come to their full size, and begin to run, as the phrase is, or 

 retreat from the marshes, and disperse through the adjacent up- 

 lands, often committing very extensive ravages in their progress. 

 Corn-fields, gardens, and even the rank weeds by the way-side 

 afford them temporary nourishment while wandering in search of 

 a place of security from the tide and weather. They conceal 

 themselves in walls, under stones, in hay-stacks and mows, in 

 wood-piles, and in any other places in their way, which will afford 

 them the proper degree of shelter during the winter. Here they 

 make their coarse hairy cocoons, and change to chrysalids, in 

 which form they remain till the following summer, and are trans- 

 formed to moths in the month of June. In those cases where, 

 from any cause, the caterpillars, when arrived at maturity, have 

 been unable to leave the marshes, they conceal themselves be- 

 neath the stubble, and there make their cocoons. Such, for the 

 most part, is the course and duration of the lives of these insects 

 in Massachusetts ; but in the Middle and Southern States two 

 broods are brought to perfection annually; and even here some of 

 them run through their course sooner, and produce a second 

 brood of caterpillars in the same season ; for I have obtained the 

 moths between the fifteenth and twentieth of May, and again be- 

 tween the first and the tenth of August. Those which were dis- 

 closed in May passed the winter in the chrysalis form, while the 

 moths which appeared in August must have been produced from . 

 32 



