THEORY OF EVOLUTION 



omTTTTD 

 CTDTTTnD 



VESTIGIAL 



LONG 



(nTTTTTTD 



GAMETES 



CHI I HID 



OTTTTTTTD 



(IIIIIIIID 



B- 



ciiiniiii) 

 aiiiiiiiD 



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

 sophila ampelophila) with long wings and a mutant fly with 

 vestigial wings. 



