188 THE ENTOMOLOGIST. 



they will commence one, and start their first journey in life : 

 one has aheady left the batch, and is making its way up the 

 twig, and evidently leaves behind something which serves as 

 a guide to those still wandering over the batch of eggs, for 

 first one, then another, follow ; and now there is a string of 

 them marching in single file : how strictly they follow the 

 leader ! No ! one appears to have lost the trail, and is pass- 

 ing up a side branch, but, discovering his error, " tries back," 

 and has again fallen into the line of march. All are now 

 assembling near the tip of the twig to repose, ere they com- 

 mence feeding. When at rest tliey adhere b}' the claspers, 

 the anterior portion of the body being erect : they closely 

 resemble, in colour, shape and size, those little black stumps 

 so common on the twigs of the birch. But while our atten- 

 tion has been taken up with this company, the remaining 

 portion of the larvae have gone in another direction : having 

 failed to " strike " the original trail, one started on his own 

 account, each subsequent individual following the trail he 

 happened to fall in with. Thus the produce of this batch of 

 eggs has become divided into two companies; it is quite 

 likely, however, that some days hence, when removing in 

 search of fresh food, they will each descend their respective 

 twigs, passing up the main stem, and fall into the same trail, 

 becoming united, probably to be again divided at a subse- 

 quent migration. 1 would for a moment draw your attention 

 to the shells which the larva; have just quitted : while 

 tenanted they were of a dark, rich, fleshy brown, much re- 

 sembling the twigs on which they were laid ; but empty they 

 are very conspicuous, and might be mistaken for opals or 

 pearls, which appearance they will retain : a well-ibrmed set 

 is a desirable addition to a cabinet, and, with the imago and 

 pupa-shell, form an interesting and instructive historic group. 

 Upwards of a week has now elapsed, and the larva? have 

 ceased to eat ; the body has thickened, until the skin has 

 become Adl and stretched ; the head has slipped out of its 

 old cover, which is empty and transparent, the head itself 

 having passed back into the next segment of the skin, which 

 finally bursts down the back, and is slipped off, segment 

 alter segment, until it is gathered into a little heap behind, 

 when the larva draws out the last segment, and then reposes, 

 after having accomplished the moult, and passed one of the 



