342 Biology in America 



ilies, or even orders of animals. The " monarch" butterfly 

 already mentioned is imitated by the "viceroy," a species 

 belonging to another genus. In* South and Central America 

 occur groups of inedible butterflies, the Heliconidse and 

 Danaidae, which are imitated by various species of edible 

 butterflies and moths, mostly the Pieridae, the chief repre- 

 sentative of which in the United States is the common cab- 

 bage butterfly. Many a fly has adopted the habit of a wasp 

 or a bee, and the resemblance is so perfect that only the 

 closest scrutiny reveals the deception. But perhaps the most 

 curious of Nature's masquerades is that played by an ant 

 and a "tree-hopper" in the Amazon region, the latter very 

 closely imitating the former as it carries on its back a leaf, 

 which it has cut for food. 



Why all this counterfeiting in nature? Of what advan- 

 tage is it to two animals to be almost exact replicas of one 

 another? Or is it counterfeiting? May not these remark- 

 able resemblances be mere accidents of variation, after all? 

 The Darwinians are, as usual, ready with an answer. Ac- 

 cording to Bates, a very real advantage in the life and death 

 struggle of the animal world is afforded certain innocuous 

 species by their resemblance to other species which are pro- 

 tected from their enemies by foul taste, or odor, or other 

 unpleasant quality. A bird which has learned to respect a 

 wasp by reason of its sting, will be very wary about seizing 

 a fly which resembles a wasp, even though the former might 

 prove a delicious morsel, did the bird only know it, while' 

 the "tree-hopper" is protected by its resemblance to a leaf- 

 cutting ant, because of the bitter taste of the latter. 



Occasionally two species of insects, each protected by some 

 disagreeable quality, resemble each other. What advantages 

 here, if both are self -protected species, in mutual resemblance 

 between them? But the staunch Darwinian is at no loss 

 for an explanation; for, he argues, if two unpleasant insects 

 look alike, their enemies will have only one pattern of color 

 to learn in order to avoid them both; whereas if they each 

 had a different pattern they would have two patterns to learn, 

 and in doing so would sacrifice twice as many insects as under 

 the present arrangement. 



There are a few species of animals which wear a white 

 patch on the rump or tail; for example, the white tail of 

 some species of deer and rabbits and. the white rump patch of 

 the antelope. Could anything so conspicuous be without*, 

 significance? Certainly not, according to the Darwinians, 

 for were it not for such ' ' recognition marks, ' ' how could the 

 young follow their mother or the herd its leader, when pur- 

 sued by some swift and savage foe? 



