SEX RATIOS IN DROSOPHILA AMI'KLOl'HII.A. 



II 



line showing the next best ratio 34 : I was used instead. He was 

 mated with five wild females, great care being taken to use only 

 virgin females, with the following results: 



TABLE III. 



The father of another good line with a sex ratio of 10 : i was 

 also crossed with two virgin wild females and the following results 



obtained : 



TABLE IV. 



Pair. 



No. of Females. 



No. of Males. 



Ratio. 



No. I 

 No. 2 



89 



47 



103 



50 



Eight males were taken promiscuously from the four lines 

 showing the four best sex ratios and crossed with virgin wild 

 females, with results as follows: 



TABLE VI. 



All of these results seem to show conclusively that the ab- 

 normal sex ratio is not caused or influenced by the male and it 

 seems probable that it is to the female we must look for a further 

 explanation. This conclusion, therefore, eliminates one of the 

 possible explanations for an excess of females, namely, that the 

 male-producing sperm are non-functional. 



