Inbreeding 



193 



the mother and more than other A-mothers. Their productive- 

 ness is nearly the same as that of the M- and N-series. In other 

 words, the male has transmitted the greater productiveness of his 



Average 

 No. Young 



nr 



M 



Generation I 3 

 Octll90a 



11 13 15 

 JonelOOi 



17 19 21 23 25 28 

 Oct;i9(H jin.i905Apr.1905 



Fig. 19. Curve of productiveness of fertile pairs of M- and N-series of Pomace 

 fly. (After Castle.) 



race to his offspring. Complete sterility, however, appeared 

 more often among the daughters than in the M- and N-series; 

 and in this respect the influence of the A-series is observed. 

 Conversely, if a female of the M- or N-series is mated with a 



