THEORY OF EVOLUTION 



49 



amnuD 



CTTTTTTTTD 



VESTIGIAL 



LONG 



GAMETES or F, 



CTTTTTTTTD 



(rTTTTTTTD 



(mTTTTTT) 



CIIIIIIIID 



anmnD 



FIG. 19. Diagram illustrating a cross between a fly (Dro- 

 sophila ampelophila) with long wings and a mutant fly with 

 vestigial wings. 



