COLOR IN ANIMALS 147 



Wallace interprets some of the very distinct marks on 

 different birds, such as the white outer tail feathers which 

 show in flight, and the streaks and spots about the head 

 and neck, as recognition marks, by which the individuals of 

 the same species recognize each other, often at consider- 

 able distances. Such marks are seen in our common kill- 

 deer and in the night-hawk (Plate 82). Probably this is a 

 true explanation of one use of such marks. 



Confu sing color a tion. 



Dr. C. Hart Merriam has suggested another use for 

 certain color markings that have sometimes been described 

 as signals or recognition marks. All must have noticed 

 that many of the butterflies have the upper surface of 

 the wings brightly colored, while the under surface is dull, 

 and that these forms, when at rest, close the wings, dis- 

 playing the protectively colored under surface. This is 

 markedly true of the beautiful leaf-butterfly, Kallima inachis, 

 (Plate 83, A and B\ These insects are very noticeable 

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

 their sudden disappearance is most startling and confusing, 

 greatly increasing the difficulty of observing their resting- 

 place. Many of the moths, which, when at rest, hold the 

 posterior wings covered by the front wings, show a very 

 similar condition, the back wings being brilliantly colored 

 above, while the front wings are dull (Plate 83, G, H, and K\ 

 These moths do not fly by day, unless disturbed, and will be 

 well protected by their dull color. In flight, however, the 

 bright color of their posterior wings is very noticeable and 

 serves to make their disappearance more disconcerting when 

 they alight. The yellow or red under-wings of grasshoppers 



