ADAPTIVE COLORATION 



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plexippus. The latter species, or " model," appears to be un- 

 molested by birds, and the former species, or " mimic," is 

 thought to secure the same exemption from attack by being 

 mistaken for its unpalatable model. The common drone-fly, 

 Eristalis tenax (Fig. 244, B) mimics a honey bee in form, size, 



FIG. 244. 



Protective mimicry. A, drone bee, Apis mellifera; B, drone fly, Eristalis tenax. 



Natural size. 



coloration and the manner in which it buzzes about flowers, 

 in company with its model; it does not deceive the kingbird 

 and the flicker, however. Some Asilidse are remarkably like 

 bumble bees in superficial appearance and certain Syrphus flies 

 mimic wasps with more or less success. The beetle Casnonia 

 bears a remarkable resemblance to the ants with which it lives. 

 The classic cases are those of the Amazonian Heliconiidae 

 and Pieridae, in which mimicry was first detected by Bates. 

 The Heliconiidae (Frontispiece, Fig. i) are abundant, vividly 

 colored and eminently free from the attacks of birds and other 

 enemies of butterflies, on account of their disagreeable odor 

 and taste. Some of the Pieridae a family fundamentally dif- 

 ferent from Heliconiidae imitate (Frontispiece, Fig. 2) the 

 protected Heliconiidae so successfully, in coloration, form and 

 flight, that while other Pieridae are preyed upon by many foes, 

 the mimicking species tend to escape, attack. 



The family Heliconiidae, referred to by Bates, comprised 

 what are now known as the subfamilies Heliconiinae, Itho- 

 miinae and Danainae; similarly, Pieridae and Papilionidae are 

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