12 BRITISH BUTTERFLIES. 



great proportion of their larvae lead solitary lives, e.g., the Urbicolids, the 

 Euralids, the Satyrids, and, with few exceptions, the Nymphalids, Pie- 

 rids, and Papilionids, and, between the absolute solitary life of many 

 species and the social life of Euvanessa antiopa, there is almost every pos- 

 sible intermediate condition. Usually the $ butterfly lays her eggs singly, 

 often only one on a plant, and these at considerable distances apart, and, 

 to this plant, the larva, in its early life at least, is often absolutely restricted. 

 On the other hand, the $ s of other butterflies lay several eggs on a 

 plant, usually on different leaves, but sufficiently numerous that 

 several young larvae may have to exist on the same plant. In other 

 cases, the eggs are laid in small batches, the young larvae living in com- 

 paratively close companionship during their early stages, but spreading 

 widely as they get older, and often evidently under the pressing- 

 necessity of seeking fresh feeding-places, whilst, in cases where the larvae 

 are strictly gregarious in their younger stages, the 5 parent laying 

 her eggs in a large mass in one place, and the young larvae spinning 

 silken webs to form a common home, the stress of food-conditions 

 leads them to spread as they tend towards maturity, and a more or less 

 solitary life is passed in the later larval stages ; indeed, the number 

 of butterflies that retain the gregarious habit entirely throughout 

 larval life is exceedingly small. The return of activity in early spring, 

 after a long-continued hybernation, is often the signal for a break-up 

 of the society, in many gregarious species that hybernate en masse 

 within a common web, but it also happens that exactly the same 

 habit is observed in gregarious non-hybernating butterfly larvae, e.g., 

 Aglais urticae. 



Of this particular view of the question, Scudder writes (Butts. New 

 England, i., p. 671) : "As a general rule butterflies live solitary lives 

 throughout their entire existence. The mother lays an egg here and 

 there upon a shoot suitable for the food of its young, and here the 

 caterpillar takes up its abode with more or less wanderings. In two 

 of the four families of butterflies there is scarcely an exception known 

 to this rule, but, in the Nymphalids, and in a few instances in the 

 Papilionids, caterpillars, during at least a portion of their lives, are 

 more or less gregarious. Whenever the caterpillars are strictly 

 gregarious, the eggs are invariably laid in clusters ; there are, how- 

 ever, some butterflies which lay their eggs in small clusters, whose 

 caterpillars are not properly gregarious ; yet all such are closely 

 related to others whose caterpillars are gregarious, so that we find 

 every gradation from solitary to social. There are also some cater- 

 pillars which are gregarious in their early life, but afterwards part 

 company ; in such cases, the caterpillar usually hybernates, and its 

 social life lasts in some degree throughout the autumn and winter, the 

 company dispersing at the renewal of activity in tbe spring ; indeed, 

 in almost all cases, the association is most conspicuous in early life, 

 when the caterpillars feed in rows upon the same leaf in such close 

 proximity, that it would seem to interfere with convenience. Some- 

 times this is the only mark of their social nature, but, as all caterpillars 

 spin more or less silk in moving about, a web of greater or less extent 

 generally accompanies a colony, and, in some cases, the community 

 constructs a close structure, within which they retire to rest or moult. 

 A Mexican butterfly, closely allied to our sulphurs, constructs a web, 

 first noticed by Hardy, which is nearly as close as parchment. With 



