64 BUTTERFLIES 



the instinct acts. A parent butterfly that in its 

 early life has been nourished upon willow has no 

 means in the winged condition of tasting the wil- 

 low to recognize it, its organs for obtaining food 

 being suited only for liquid nourishment. 



Nor can it be by the color of the object. It 

 is true that butterflies are attracted by flowers 

 through their means of vision. Interesting stories 

 are told of their being deceived by painted or arti- 

 ficial flowers. But in these cases there is no rea- 

 son to suppose that it is anything but the tint in 

 mass that attracts them to the spot. Pray how 

 does the green of one plant differ from that of all 

 others ? Anatomy and experiment both seem to 

 teach that butterflies have no power of vision for 

 any such discrimination as is required of them in 

 selecting special food plants for their young ; which 

 yet they discover in an unerring manner. 



There remains apparently nothing but smell. 

 That their sense of smell is exceptionally acute is 

 plain from facts coming from a quite different 

 source, which are given in another place-, under 

 Aromatic Butterflies. The production of odor 

 implies the recognition of odor, and inasmuch as 

 the organs through wdiich the odor is known in 

 many cases to be emitted exist in a very much 



