72 BKITISH BUTTERFLIES. 



so well protected ; one could usually detect a larva on a stem at the 

 first or second glance and no amount of searching revealed any more. 



CHAPTEE XIV. 



THE RESTING-HABITS OF BUTTERFLY LARVAE. 



The question of the resting-habits of butterfly larvae opens up a 

 series of phenomena connected with their vital energies that are most 

 difficult of explanation. The resting-habits cannot all be dealt with 

 under one category, for there is considerable difference between the 

 lethargy following a meal, the longer period of time when preparing 

 for, and undergoing, a moult, and, finally, the very long period which some 

 butterfly larvae undergo during their hybernation, when all the active 

 functions appear to cease, and when a larva makes scarcely a sign of 

 life, maintaining for weeks, and months maybe, a fixed position from 

 which it never stirs or moves, and this, during the time which we 

 have learned to look upon as the most active of all the early stages, 

 that stage which is utilised not only for eating so that full growth 

 may be attained, but also that material may be stored for the 

 metabolism of the pupal stages and the formation of the imago. 



The simplest of these resting-habits is that which takes place after 

 a larva has eaten a meal. Possibly all butterfly larvae do this, and 

 the position that they take up during this period is so important, that 

 it may be said that it is to meet their requirements for protection at 

 this time that the various schemes of protective resemblance in 

 butterfly larvae, probably slightly different in each individual case, 

 have been brought about and perfected. Some hide themselves 

 beneath a leaf, e.g., Rnralis betidae, where the larva looks like a spot 

 of sunlight from beneath ; or they crawl down to the stem of the 

 plant as in the case of Anthocaris belia, or Euclilo'e cardamines, where 

 they become, with their lines and markings, a part of the stem, or 

 they choose an exposed position, as in the case of Charaxex jasius, when 

 it is protected by its general resemblance to its surroundings. This 

 latter species spins a silken carpet on the upper surface of a leaf on 

 which to rest, going to neighbouring sprays for food, and returning to 

 the silken pad to rest, basking a good deal in the sun during the day, 

 not changing its station often, sometimes probably not at all during 

 the whole of the larval life. Its scheme of general cryptic coloration 

 is excellent (Knt. Rec, ix., p. 193). The value of thus retiring during 

 the period of digestion, and the importance of the position they take 

 up when thus at rest, are self-evident, for it is whilst the larva is 

 moving about that it is in most danger from its many enemies, and, 

 conversely, it is safest when hidden and at rest. The fact that a large 

 percentage of butterfly larvae feed only at night, and rest hidden during 

 the whole of the day, suggests an even enhanced measure of protection 

 to such larvae, during these daily resting-periods ; thus the larvae of 

 Laeosopis roboris rest during the day time, huddled up close together 

 on the shady side of the stem of an ash, near the ground, and only 



