Lnbreeding 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 
Ne oO Young 
450 
—— 
os 
q 
= 
_—— 
_ 
= 
ad 
ae 
= 
eucaces or 
Genemtiont 3 6 7 9 M1 13 16 17 19 2] 23 O57 28 
Qcti1908 ! Tune 1904 Oct 1904 Jan.1905 Apr. 1005 
Fic. 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 
ce) 
