ON THE EARLIER STAGES OF COLIAS HYALE. 5 



In order to test this hypothesis, a weak solution of hydro- 

 cyanic acid was obtained,* and some experiments made therewith. 

 To my great disappointment it was found, however, that this weak 

 solution of HON had no effect at all upon the wings immersed in 

 it. The experiments were varied in several different ways, but 

 the attempt to produce the cyanide red proved a total failure ; 

 and the result, up to the present, is, therefore, that the reddening 

 is due not to hydrocyanic acid as such, but to potassium cyanide, 

 or to potassium C3'anide and hydrocyanic acid together. That an 

 actual combination does take place between the yellow pigment 

 and the potassium cyanide (or the hydrocyanic acid, under the 

 influence of potassium cyanide), I can hardly doubt. The weak 

 but positive effect of sodium cyanide on the one hand, and the 

 great number of wholly negative results obtained — as now to be 

 related — from a number of varied reagents, seem to justify this 

 view ; but it is proposed, as opportunity offers, to carry forward 

 this investigation in several directions. 



(To be continued.) 



FUETHEE EEMARKS ON THE EAELIEE STAGES OP 

 COLIAS HYALE. 



By F. W. Fkohawk, F.E.S. 



It is doubtful if either of our two species of Colias ever 

 survive an English winter in a state of nature, excepting perhaps 

 in the mildest and most sheltered spots on the southern coast, in 

 whatever stage they might undergo hybernation. I believe it is 

 generally supposed that they hybernate in the imago state, which, 

 however, is contrary to my observations respecting C. hyale, and 

 from the following notes I think it may safely be presumed that 

 in a natural state hyale passes the winter in the larval condition ; 

 at the same time I feel positive that but very few survive the 

 climatic changes of an English winter, which idea is strengthened 

 by the mortality occurring among a large number of C. edusa 

 larvae, 170, which I had feeding and growing satisfactorily until 

 the middle of last October, when a week of severe wintry weather 

 set in, causing all the larvse to cease feeding, and, with few 

 exceptions, remain motionless. Many died daily, and, excepting 

 a few full-grown larvae, none survived the effects of that cold 

 sunless week, although mild and bright weather reappeared. 

 Undoubtedly the first severe frost would be fatal to larvae feeding 

 in exposed places, which would account to a great extent for the 

 general absence of Colias throughout the country in ordinary 

 years. When a " Colias year" comes round, it is occasioned by 



* The ordinary B. P. 2 p. c. solution of the acid was used. 



