In the Face of the Cold 



after another week they were again brought in, when only 

 eleven were restored to life; a fourth time they were exposed to 

 the winter temperature, and only two returned to life on being 

 again brought into the cabin; these two survived the winter, 

 and in May an imperfect Laria was produced from one, and six 

 flies from the othei'o" 



The foregoing account seems to verify more thoroughly the 

 stories that have been told than anything else I have been able to 

 discover within the limits of entomological literature, but does 

 not conclude argument. It would be interesting in these days, 

 when methods of artificial freezing have been so highly per- 

 fected, to undertake a series of experiments to prove or disprove, 

 as the case may be, the view which has been held since the time 

 of the ancients. There is here a field for nice investigation on 

 the part of some reader of this book. In making the experiment 

 it probably would be well to select the larvae of species which 

 are known to hibernate during the winter and to be capable of 

 withstanding a great degree of cold. 



The effect of cold suddenly applied to the chrysalids of 

 butterflies at the moment of pupation is often to produce re- 

 markable changes in the markings. The spots upon the wings 

 of butterflies emerging from chrysalids thus treated are frequently 

 rendered more or less indistinct and blurred. The dark mark- 

 ings are intensified in color and enlarged; the pale markings 

 are also in some cases ascertained to experience enlargement. 

 Many of the strange and really beautiful aberrations known to 

 collectors have no doubt been produced by the action of frost 

 which has occurred at the season when the larva was pupating. 

 The species believed by the writer to be most prolific in aberra- 

 tions are species which pupate early in the spring from cater- 

 pillars which have hibernated or which pupate late in the 

 autumn. Some are species found at considerable altitudes 

 above sea-level, where late frosts and early frosts are apt to 

 occur. A number of very beautiful experiments upon the effect 

 of cold upon the color of butterflies have been made in recent 

 years, and some very curious phenomena have been observed. 

 The writer has in his collection a considerable number of 

 strikingly aberrant specimens which emerged from chrysalids 

 treated to a sudden artificial lowering of the temperature at the 

 critical period of pupation. 



225 



