1890.1 185 



ON THE BRITISH MACRO-LEPIDOPTERA WHICH HIBERNATE IN 

 THE PERFECT STATE. 



BY THE LATE fi. C. E. JORDAN, M.D. 



Many of our Lepidoptera sleep through the winter months, or 

 pass through this portion o£ the year in a state more or less bordering 

 on torpidity. The larvae o£ some of these feed on deciduous trees, 

 others on shrubs, others again on low plants ; there is no bond con- 

 necting them together, they are gathered from all groups, save, of 

 course, such Bomhyces as have only rudimentary mouths, with them 

 prolonged sleep would be impossible, for the simple physiological 

 reason that they could have no store of food to fall back upon. In 

 eases of true hibernation, the eggs are in all probability deposited 

 after the winter is over ; the process of ovipositing would be too 

 exhausting for life to be prolonged much afterwards, nor would there 

 seem to be any reason for such prolongation. 



Hibernating insects must not be confounded with those which 

 appear in the winter months, such as Lasiocampa populi, the Hibemice, 

 and many others, curiously to these an apterous female, which is not 

 easily blown about by winter storms, seems an advantage, but in truly 

 torpid Lepidoptera the wingless protection never occurs. 



Amongst butterflies, there is, first in order, Gonepteryx rhamni. 

 Both sexes undoubtedly live through the winter, reappearing with the 

 first bright days of spring ; many interesting facts concerning this 

 hibernation were brought forward in this Magazine in answer to a 

 paper by Mr. Kenrick. The ova are laid generally in April or May ; 

 when impregnation takes place is unknown to me. 



Colias Edusa. — Here we have a case of greater difiiculty. The 

 usually received opinion is the traditional one, that the female lives 

 through the winter, and deposits her eggs in the spring. This is cer- 

 tainly not always true : I have myself twice watched the female 

 depositing her eggs (or, rather, egg, for they are laid singly) on clover 

 in October and November ; but, is the winter sleep ever true, that is, 

 in Britain? In the south of Europe, Colias JEdusa may be met with 

 on all the warmer winter days, but this only implies that it lives on 

 by a kind of sufferance, just as it may be occasionally seen in Devon 

 on a bright day in the very early part of November. That specimens 

 of C. Edusa may be sometimes caught during June in England is 

 certain, and that they may always be so found in Switzerland is equally 

 sure, and once in the Rhone Valley a dilapidated female was seen by 

 me depositing her eggs during that month; but all the June specimens. 



