BRITISH BUTTERFLIES. 



CHAPTER I. 



THE AESTIVATION AND HYBERNATION OF BUTTERFLY LARV.E. 



We have already, in the previous volume (pp. 72 etseq.), dealt with 

 certain of the resting-periods of butterfly larva?, but the resting-period, 

 by means of which many larvae, in a lethargic state, pass the autumn 

 and winter months, and a small number, most of the summer, as well 

 as the autumn and winter, months, is exceedingly interesting, and 

 must have come under the observation of every field naturalist. This 

 phenomenon, which may extend from only a few weeks in the depth 

 of winter, to many months, e.g., July to March, is usually known as 

 "hybernation," although Scudder attempts to differentiate (Butts. New 

 England, p. 551) between a summer and winter rest, calling the former 

 aestival portion "lethargy," and the latter, "hybernation." To this we 

 shall refer later. 



It is a well-known fact that all species of butterflies, at least in 

 north temperate climates, pass the winter in the same stage (at any 

 rate there are few well-authenticated instances in which this is not so, 

 Pararge egeria being the only one known to us), and, although this may 

 be the egg, larva, pupa, or imago, it is always (with the rare exceptions 

 above noted) the same for the same species. The proportion of butter- 

 flies that hybernate as larva? in a torpid state, in temperate regions, is a 

 comparatively large one, and among our British butterflies we find the 

 following : — Nisoniades tages, Cyclopides palaemon, Augiades sylvanus, 

 Adopaea flava, Cupido minima, Aricia astrarche, Polyommatus icarus, 

 Agriades bellargus, Lycaena avion, Runricia pklaeas, Chrysophanus dhpar, 

 Aporia crataegi, Colias edusa, C. hyale, Dryas paphia, Argynnis 

 aglaia, Issoria lathonia, Brenthis euphrosyne, B. selene, Melitaea cinxia, 

 M. athalia, M. aurinia, Limenitis sibylla, Apatura iris, Pararge egeria 

 (also as pupa), P. megaera, Epinephele ianira, E. tithonus, Erebia 

 aetltiops, Melampias epiphron, Coenonympha typhon, C. pamphilus, 

 Enodia hyperaiithas, Hipparchia semele, and Melanargia galatea, i.e., 

 considerably more than one-half of our butterfly fauna, whilst some 

 doubt is attached to the particular stage in which two other species, 

 usually reputed to pass the winter as larvae, really do hybernate. 

 These are Thymelicus acteon and Everes argiades. 



But, besides these, it is a remarkable fact that some, possibly all, 

 of the butterflies known to us to hybernate in the egg stage, really do 



