484 



THE AMERICAN NATURALIST 



[Vol. L 



in each succeeding generation. The females produced by 

 this group of males mated to class 1 females only, would 

 occur in the proportion of "over 30" females 75 per cent., 

 "under" 25 per cent. The ratio 1:2:1 among the males 

 maintains itself after once reached, so long as class 1 fe- 

 males only are used for mates. 



The same ratio is reached if it be assumed that all nine 

 classes of males exist in equal numbers at the start and 

 that they are bred in each generation in the proportions 

 thrown by the preceding generation and only to class 1 

 females. 



The assumptions made have been chosen as those most 

 likely to lead to decreased egg production or to a main- 

 tenance of production on a level. I have not worked out 

 many of the possible assumptions, but as long as only fe- 

 males belonging to classes 1 or 2 are used in the matings, 

 males of higher classes, i. e., classes 1, 2, etc., are thrown 

 by those of the lower classes in the same manner as 

 pointed out for classes 5, 6 and 9, so that eventually males 

 of the higher classes come to exist in definite ratios. 



If class 2 females (L^I^H^U) only are bred, somewhat 

 different results are secured. If males belonging to classes 

 1, 2, 3, 4, 7 and 8 are used in equal proportions at the 

 start (classes 5, 6, 9 being omitted for reasons stated 

 above) then in the seventh generation nearly 98 per cent, 

 of the males will belong to class 1, the other 2 per cent, 

 belong to classes 2 and 3, and these will diminish one half 

 in each succeeding generation. The final result, then, 

 should be a race of high producers. 



Since it has been shown that when class 1 females are 

 used exclusively in the matings, that eventually a stable 

 flock of birds is produced in which male classes 1, 3 and 7 

 exist in a definite ratio, and since if class 2 females are 

 bred exclusively a flock consisting solely of high pro- 

 ducers will result in time, and since class 1 females mated 

 to males of classes 1, 3 and 7 throw 25 per cent, class 2 

 females, 50 per cent, class 1 females and 25 per cent, 

 mediocre producers, it would seem inevitable that eventu- 



