THE AESTIVATION AND HYBERNATION OF BUTTERFLY LARVAE. d 



or from the attacks of enemies, and also because, in no case, do these 

 apparently helpless little creatures, generally but 2mm. or 3mm. long, 

 construct any sort of nest or retreat for their common or individual 

 protection. They merely seek hiding-places separately in curled leaves, 

 on the ground, in crevices of bark and similar spots, where they are 

 certainly not out of the way of mites and ants. Neither have they 

 any appendages which are not shared with other juvenile caterpillars 

 that do not hybernate. There is no evidence, from any poverty 

 of butterflies in these groups, that they do not retain as good a hold 

 upon the fauna as those species which do not pass what would seem 

 to ' be so perilous a winter ; on the contrary, our Satyrids and 

 Argynnids are plenty enough on the wing." 



At the opposite end of the scale, compared with the hybernating 

 stage of Dry as paphia, Argynnis aglaia, etc., are Niso7iiad.es tages, 

 Cyclopides palaemon, and Cupido minima, for these species hybernate as 

 fullgrown larvae, the last-named being usually fullfed in early or mid- 

 July, when it becomes dormant, and not pupating till the following 

 May ; Buckler notes larvae full-fed July, 1872, pupated June 3rd, 

 1873, with a larval existence of more than ten months. Similarly, 

 Nisoniades tages is fullgrown at the end of July, when it spins a silken 

 hybernaculum, remaining unchanged therein all the winter (even in a 

 warm room), and pupating during the following April, whilst the larva of 

 Cyclopides palaemon, fullfed about the middle of August, remains in its 

 • hybernaculum till early April, when it becomes restless, and soon after- 

 wards pupates. 



We have already noted that more than one-half of our British 

 butterflies hybernate in the larval stage, and one suspects that this 

 percentage is well-maintained throughout the north temperate zone. 

 Speaking of New England, Scudder says (op. cit., p. 688) : "Certainly 

 a quarter, not unlikely one-half, of our butterflies survive the winter 

 as caterpillars ; in the larger part of these the existence of the species 

 depends upon their power of survival in this condition. Most of them 

 pass the winter partly grown ; some, as the species of Thanaos and 

 P/wlisora, fully growm, partaking of no further nourishment when 

 the winter is passed, but changing to chrysalids almost or actually 

 before their foodplant puts forth its leaves in the spring. Others still, 

 and among these are most Satyrinae and Argynnidi, winter as young 

 larvae just hatched from the egg, generally, perhaps always in New 

 England, before they have touched a morsel of vegetable food, though 

 their natural fcodplant, upon which they were born, still offers 

 sufficiently tender leaves .... Of those that pass the \yinter 

 half-grown, we may specify Cissia, Basilarchia, Brenthis, all the New 

 England species of Melitaeidi, probably the species of Ettrymus, and 

 not improbably most of the Pamphilidi, of whose complete trans- 

 formations we know far too little." As far as our Palaearctic species 

 are concerned, no such sweeping generalisations can be made with 

 most of these groups, for, although Nisoniades (tages) and Cyclopides 

 (palaemon) hybernate as fullfed larvae, and Aug lades (syhanus) as a 

 half-grown one, yet Urbicola comma, another Pamphilid, hybernates as 

 egg; and, whilst the large Argynnids hybernate as newly-hatched larvae, 

 or larvae in the egg-shell, and Brenthis as half-grown larvae, there are few 

 European Satyrids, whose life-history we know, that adopts the Argynnid 

 habit, although Coenonympha matheivi, Chapman informs us, does so. 



