274 HAftOLD’S DISCUSSIONS. 
The rear marks of the antelope may suggest the 
same explanation. Color for recognition is only 
Fig. 125.—The upper butterfly is poisonous to birds, who do not 
molest it. The second one is not poisonous, but imitates in 
form and color the first, and thereby escapes seizure by birds. 
found in animals of a timid nature who depend upon 
flight for safety. 
