HISTORY OF ZOOLOGY. 



57 



into existence. Among the grasshoppers also there are 

 imitations of leaves, like the "walking-leaf," Phy Ilium sic- 

 cifolium, P. Scythe, while other very nearly related forms 

 again more or less completely approach the appearance of 

 dried, sometimes of thorny twigs (Fig. 12, a and b). 



B. 



FIG. ii. Leaf-butterfly. A, Kallima paralecta, flying; a, at rest. (After Wallace.) ff, 

 Siderone strigosus, flying; b, at rest. (After C. Sterne.) 



Examples of Mimicry. Very often insects are copied 

 by other animals. Certain butterflies, Heliconia, fly in 

 large swarms, clumsy and yet unmolested by birds, because 

 they contain a bad-tasting mass of fat. Another species 

 of butterfly accompanies them, Picridic, which do not 



