THEORY OF EVOLUTION 105 





FIG. 53. Group I. (See text) 



duces the notch in the wings is also a recessive 

 lethal factor ; because of this latter effect of the 

 character no males of this race exist, and the 

 females of the race are never pure but hy- 

 brid. Every female with notch wings bred 

 to a wild male, will produce in equal num- 

 bers notch winged daughters and daugh- 

 ters with normal wings. There will be half as 

 many sons as daughters. The explanation of 



