ADAPTIVE COLORATION 185 



by sharing its immunity from destruction. Though it attains its highest 

 development in the tropics, mimicry is well illustrated in temperate 

 regions. A familiar example is furnished by Basilarchia archippus 

 (Fig. 244, B), which departs widely from the prevailing dark coloration 

 of its genus to imitate the milkweed butterfly, Anosia plcxippus. The 

 latter species, or "model," appears to be unmolested 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. 245, B) mimics a honey bee in form, 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 Asilidae are remarkably like bumble bees in superficial appearance 

 and certain Syrphus flies mimic wasps with more or less success. The 



A 



FIG. 245. Protective mimicry. A, drone bee. Apis mdlifcra; B, drone fly, Erislalis tcnax. 



Natural size. 



beetle Casnonia bears a remarkable resemblance to the ants with 

 which it lives. 



The classic cases are those of the Amazonian Heliconiidae and Pieridas, 

 in which mimicry was first detected by Bates. The Heliconiidae 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 different from 

 Heliconiidae imitate the protected Heliconiidae so successfully, in 

 coloration, form and flight, that while other Pieridas 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, Ithomiinae and Danainae; 

 similarly, Pieridae and Papilionidae are now often termed respectively 

 Pierinas and Papilioninae. Ithomiinae are mimicked also by Papilio- 

 ninae and by moths of the families Castniidae and Pericopidae. 



