VI. 



COLOK-RELATIONS OF CHRYSALIDS TO THEIR 

 SURROUNDINGS 



It has long been known that there is in many 

 instances considerable variation in the color of the 

 chrysalids of certain butterflies, and that in not a 

 few instances we find a dimorphism more or less 

 accentuated. The most frequent difference that 

 has been noticed has been the prevalence on the 

 one hand of green tints, on the other of dark gray 

 or brown. Now when we recall that the common- 

 est places chosen by caterpillars of butterflies for 

 pupation are either amongst the foliage of the 

 plant on which they have fed, or on the other hand 

 pendent from, or attached to, the twigs or trunks 

 of trees with their gray bark, or to stones whose 

 general color is dark gray or brown, we notice that 

 we have here general tints of much the same con- 

 trast. When we further observe that the green 

 color prevails in the chrysalids of those species 

 which commonly transform upon the leaves of their 



