HISTORY OF ZOOLOGY. 



4Y 



the npi^er side is concealed. The jDarts are so arranged that the 

 whole takes on a leaf-like form, and certain markings heighten 

 the imitation of the neuration of the leaf (fig. 11). Among the 

 numerous species of leaf-butterflies there are different grades of 

 completeness of mimicry; in many even the depredations of insects 



A 



Fig, 11.— Leaf-butterflies. A, Kallima paralecta. flying; a, at rest. (After Wallace.) 

 B, Sidcrnne strigosus, flying; Jj, at rest. (After C. Sterne.) 



is imitated; in others the form and marking are still incompletely 

 loaf-like, the marking being the first to come into existence. 

 Among the grasshoppers also there are imitations of leaves, like 

 the 'walking-leaf,' Phyllium siccifolium, P. scythe, while other 

 nearly related forms more or less completely approach the appear- 

 ance of dried, sometimes of thorny twigs (fig. 12, a and Jj). 



ExamiJiles of Mimicry. — Very often insects are copied by other 

 animals. Certain butterflies, Heliconia, fly in large swarms. 



