638 THE BUTTERFLIES OF XEW EXGLAND. 



wliere they walked out of them. There seems to be a very general negli- 

 gence in this regard among social caterpillars, where the necessity for it 

 would appear most urgent. They feed in close company always on the 

 under surface of the leaves, moving up or down, generally down the 

 plant, as they need fresh pasture, and leaving a desert behind them. Even 

 when eggs to the number of a hundred are laid on one of the smaller 

 terminal leaves, it is fully twenty -four, perhaps thirty-six hours after 

 hatching before one of the caterpillars quits the leaf; the under surface of 

 this single leaf suffices for all their wants for this time. They eat the 

 parenchyma only, but not very cleanly, the leaves having everywhere lit- 

 tle flecks of uneaten parenchyma, giving them a pitted appearance ; this 

 is in early life ; they afterwards devour the leaf itself but still spin no 

 web. They are very inactive, and cannot be roused to movement ; at the 

 most they will coil themselves into a circle and drop to the ground. The 

 latest brood of larvae becomes lethargic soon after the second moult, but 

 under fsivorable circumstances will continue feeding until October in the 

 vicinity of Boston, and by the observations of Mr. Edwards sometimes 

 arouse, pass another moult and again resume tlieir lethargy. No leth- 

 argy is observable in the other broods according to Mr. Edwards. The 

 caterpillars probably hibernate in any cranny they can find on the surface 

 of the ground, as they leave the plant and wander more or less, but still 

 to some degree in company. In this state and in this state only, appar- 

 ently, the winter is passed. They must awake early in the spring, for 

 sometimes at any rate they are full fed by the middle of May in Mass- 

 achusetts. 



Pupation. The larva attaches itself to any firm substance to undergo 

 its final changes, but, under natural circumstances, apparently not to its 

 food plant. In New England the chrysalis generally hangs nearly a fort- 

 night, but Mr. Edwards has found it to range in various places, usually 

 from six to thirteen days, sometimes prolonged to as many as thirty days. 



G-eneral life history. In New England the insect is double-brooded, 

 and passes the winter in the third and fourth larval stages. Farther 

 south there are one or more broods interpolated between these two. Near 

 Boston the first brood of butterflies appears about the middle of May*, 

 though sometimes not until toward the 25th of the month ; in central 

 Connecticut I have found the species not uncommon, probably a week out, 

 on May 15. As in the case with most species the first brood of which is 

 made up from caterpillars wintering when half grown, it does not rapidly 

 become common, not before the very end of the month, and sometimes 

 not until the first week in June ; rarely indeed is it abundant before the 

 first of June, females are, I believe, never taken before the 21st of May, 



* Dr. Merrill notes the capture of three this must l>o an error, through transposition 

 specimens in Andover, Mass., April 27th; l)ut of labels, or otherwise. 



