THE BACKGROUND OF DARWINIS:\I: ADAPTATIONS 



209 



*^Its wings," says Herbert, "when upturned, represent on their 

 underside a perfect copy of a leaf with a midrib and a regular suc- 

 cession of side veinings. Differently colored spots on the wing imi- 

 tate patches of decay and mildew, while the prolonged tail of the hind- 

 wing, which touches the stem in the sitting posture of the butterfly, 



Fig. 41. — Kallima, the "dead-leaf butterfly." (From Jordan and Kellogg.) 



makes it appear as though the leaf was directly growing out of the 

 stem." It is only when at rest upon the stem of a tree that the re- 

 semblance to a leaf would be effective, for it is only the under surfaces 

 of the wings that are protectively colored. The upper surfaces of the 

 wings are brightly colored and would supposedly be quite conspicuous 

 when the insect is in flight. "These insects," says IMetcalf, "are very 

 noticeable when in flight, but when they light and close the wings, their 



