THE EAKLIER STAGES OF COLIAS HECLA. 85 



take it out of doors, so that it might get some approach to its 

 natural home conditions in winter, and afterwards to force it, 

 but the winter turned out to be exceptionally mild, and by 

 January 23th, there not having been any frost, I brought the 

 larva up and placed it in a warm room. I did not have a plant of 

 A. alpimis in leaf, and so offered the larva young leaves of Colutea 

 arhorescens, which I had ascertained the previous summer it 

 would eat. On January 22nd it commenced to feed upon 

 these, and fed very slowly for several weeks, so slowly, however, 

 that its daily meal, which was usually taken when the sun was 

 shining, did not exceed a notch in a leaflet the size of an average 

 pin's head. In the beginning of March it sickened and died. 

 During the time it was feeding in the winter the size only in- 

 creased a very little, not more than a millimeter in length. In all 

 probability, to successfully rear this larva would entail its being 

 kept at a temperature below freezing point for several months. 



In its natural habitat the snow would probably be gone by 

 the middle of May. Staudinger mentions that at Bossekop the 

 first male was taken on June 18th, 1860, but it certainly was not 

 out there on the day I left, June 22nd, 1912. On my arrival at 

 Laxelv on July 11th, fully one-third of the specimens flying 

 about were more or less worn. The season was rather a late 

 one, and I should say that June 20th, as the first date of emer- 

 gence on an average season, is probably not far wrong. 



Astragalus alpinus in Lapland entirely loses all trace of 

 foliage in the winter, and until the middle of June, or rather 

 later, it does not develop sufficient new leaves to feed the larva 

 upon ; this being the case, there seem to be three possible 

 theories of its behaviour after hibernation : — 



(1) That it has an alternative food-plant. I do not think this 

 probable for, as before stated, I could not find another leguminous 

 plant in its haunts, and one cannot imagine it feeding upon 

 anything else. 



(2) That it feeds upon the roots of A. alpinus. This is pos- 

 sible, for this plant has long succulent roots, very much after the 

 style of Lotus corniculatus. 



(3) That it feeds very slowly through the summer on the 

 leaves of A. alpinus, hibernating a second time, either as a full- 

 fed larva or as a pupa. I am inclined to think that this latter 

 theory will prove the correct one. The larva I had in confine- 

 ment seemed perfectly healthy and satisfied with its daily 

 minute meal for weeks, which is just what one would expect it 

 to do in a state of nature if this theory be correct, for the leaves 

 until the middle of June are very minute and would not suffice 

 to satisfy a more vigorous appetite. But, of course, my larva 

 had not been subjected to its natural low winter temperature for 

 many months, and one does not know what effect the unusual 

 treatment received might have had upon its appetite. 



Youlgreave, South Croydon : January 13th, 1914. 



