114 Segregation of Fecundity Factors in Drosophila 



showed that their completeness depended on luck and not on any 

 knowledge possessed by the writer. 



Table I presents the data from Line I, the strain lacking in vigor. 

 Four pairs were mated, they being respectively designated as A, B, 



TABLE I. 



Breeding Record of Line I. (^ line lacking vigor and high fecundity.) 

 Pair A Pair B Pair C Pair D 



Fo .38 flies 34 flies 51 flies 28 flies 



I 1 I 1 I 1 I 1 



I I I I I I I I 



JF3 30 41 28 32 43 39 . 36 38 



r-^n A-^ r-^n r-^n r-H r-^n X^ r-H 



II II II II 11 II 11 11 



F^ 32 26 21 34 32 26 32 35 36 32 28 31 26 30 32 29 



II II II II II II II II 



F^ 30 24 26 25 34 31 26 30 42 26 28 36 25 18 34 40 



II II II II II II II II 



Fq 32 30 29 31 30 26 34 28 44 30 34 40 31 died 31 41 



II 11 II II II II I out I I 



F-i 26 21 23 24 23 21 29 34 39 24 44 39 27 25 32 



I I I I I I I I I i I I I II 



Fg 24 25 30 22 24 28 28 24 46 19 60 42 24 21 34 



I I I I I I I I I I I I I II 

 Fq 25 23 19 26 21 25 30 19 30 26 30 39 21 24 27 



II II II II II II I II 

 i^io 22 25 23 21 19 27 24 26 36 22 24 34 18 20 28 



G and B. The table shows the low state of their fecundity and also 

 the degree to which they bred true. Placed on the basis of the 



means, for comparative purposes, the last eight generations rank as 

 follows : 



F^ Mean 35-875 



The mean of the entire line, nine generations, is 29-5 and the 

 standard deviation is 7*31, giving as coefficient of variability 28-17. 

 The coefficient of variability is of little value as a means of comparing 

 the different lines owing to the fact that the units of variation are the 

 same and the means so widely separated. Therefore it would seem 



