\|.\l'l |\ I ()M)K \ I [ON 



201 



oiusf have been pre <-Mt, how< natur.d selection 



could l>e;in to operate; their origin is a question quite distinct from tha^ 



of their subsequent preservation. 



Protective Mimicry. 'I'his interesting and highly involved phe- 

 nomenon ial form of protective resemblance in whicb on 



;-..{, Anosia plexippus, the "model;" B, Basilarchia archippus, the "mimic." 



Natural size. 



imituUs the a]){)earance of another and better protected species, there- 

 by sharing its immunity from destruction. Though it attains its high- 

 f>t 'lc\ lopmc-nt in the tropics, mimicry is well illustrated in temperate 

 us. A familiar example is furnished by Basilarchia archippus 

 247, J1), which departs widely from the prevailing dark coloration 

 o! it- ^i-iiiis to imitate the milkweed butterfly, Anosia plcxippns. The 

 latter- or "model," appears to be unmolested by birds, and the 



former S] - "mimic," i> thought to secure the same exemption 



