92 
TRANSFORMATIONS OF INSECTS. 
change in the butterfly must be determined in the chrysalis 
state, and during the progress of the second metamorphosis. It 
has been proved that the duration of the chrysalis condition 
can be lengthened by placing the pupa in cold and dark places, 
or in ice, and shortened by increasing the usual amount of warmth. 
But no variation in the ornamentation of the perfect insect has 
been produced by this artificial lengthening or shortening of 
chrysalis life. So that most probably the disposition of these 
butterflies to vary has some deep significance, which refers to the 
duration of the species in time — moribund genera and species 
varying much, and new forms striving to adapt themselves to 
peculiar conditions. 
The hybernation of some of the large butterflies through the 
winter in temperate climates is very interesting. 
