100 ASSOCIATIONS AND MIGRATIONS 



at all agreeable to their tender frames. After they 

 have devoured all the leaves within the verge of their 

 covering, they set to work, and construct a new one 

 over some other roots of the same plant ; and it not 

 unfrequently happens, that several of these encamp- 

 ments are within a few feet of each other. On the 

 approach of winter, they construct a stronger tent, 

 consisting of one apartment. When the cold weather 

 sets in, they retire within it, roll themselves up into 

 a sort of ball, and lie huddled together until April, 

 when they break up their community, become solitary, 

 and continue so, till they assume the pupa condition, 



Where food is abundant, there have been many 

 instances of papilionaceous insects performing won- 

 derful migrations ; while others limit their excursions 

 to a very narrow range. The Forester, (/wo statices 

 of Leach,) has been observed in vast numbers 

 disporting on the north bank of the Serpentine, in 

 Kensington Gardens, while not a single one was to 

 be seen on the opposite bank, nor even in any other 

 spot in the neighbourhood. Professor Rennie, on 

 one occasion, observed many hundreds of the Burnet 

 Moth, (Anthrocera filipenduke of Stephens,) on the 

 north shore of the Great Cumbrya Island, at the 

 mouth of the Clyde, but not on any other part of the 

 island, nor on the opposite shore at Largs, although 

 he made a round of the island on the same day. He 

 also visited the Isle of Bute ; but did not meet with 

 a single specimen. 



Harris says, that the Marsh Fritillary (the Melitce 

 artcmis of Ochsenheimer) is so extremely local in 



