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JOURNAL OF VARIATION. 



Vol. VIII. No. 9. October 15th, 1896. 



On the hybernation of certain British Butterflies in the imago state. 



By J. W. TUTT, F.E.S. 



One would have supposed that, as butterflies are such dehcate 

 creatures, and pass a certain period of their lives in a quiescent state, 

 the pupal. Nature would have selected this for them to pass the winter, 

 and one is, therefore, much struck with the fact that Nature, showing 

 her usual abhorrence of fixed rules, does nothing of the kind, but 

 selects, as it were, each of the four stages — ovum, larva, pupa and 

 imago — through which a butterfly passes, for different species to 

 hybernate, and we find that, whilst many Thedidi pass the winter as 

 eggs, the Vaneaddi as imagines, and the Pieridi as pup?e, yet a great 

 proportion of our British butterflies hybernate in the larval state. 



One would assume, even then, that closely allied species would 

 hybernate in a similar manner, and to a great extent this is true. The 

 whole of the British Hesperids hybernate as larvae, except Si/ricJitJms 

 malvac, which hybernates as a pupa.'-'' All the British Lyca3nids hyber- 

 nate as larvse, except Plebeim aeijun and Lampides boetica, which hyber- 

 nate as eggs, and Nomiadcs semiaiy/us and Ci/aniris art/iohift, which 

 hybernate as pup^e. Again, the British Theclids hybernate in the egg 

 state, except C'allnphrt/n rubi, which hybernates as a pupa. The British 

 PiERiN^ hybernate as pupfe, except Apnria crataegi, Colias kyale and 

 C. edusa, which hybernate as larvse, and Oonepteryx rhamni, which 

 hybernates as an imago. All the British Argynnids (and Melitaeids) 

 hybernate as young larva?, except An/i/nnis adippe, which hybernates 

 as an egg (although the larva is coiled up within the Qgg all the 

 winter). All the Vanessids hybernate in the imago state, except 

 Pyrameis cardui, which probably never hybernates in the true sense of 

 the word at all. The Satyrids all hybernate as young larvae without 

 exception, unless Paran/e eijeria be admitted as such. There is then, 

 in our British fauna, variety enough among near allies in their hyber- 

 nating stages, and yet a great deal of similarity between them, 

 taken as a whole. Nor is this confined to Britain (or Europe), for the 

 Vanessids, which are spread over the temperate regions of the Old and 

 New Worlds, where the winter is very pronounced, pass the winter on 

 both Continents in the imago state. This is not difficult to understand, 

 for most of the Vanessids disclose their imagines at a late period of the 

 year, and would not have time to complete their transformations before 

 winter would overtake them. Yet, in hot seasons, both Vanessa i<> and 

 Pyraineis atalanta do, more or less successfully, get in another partial 

 * Thymeliciis lineola and Pamphila comma hybernate as eggs. 



