212 



THE SECOND-CHROMOSOME GROUP 



ruary 8, 1913; Bridges, p. 35), but this is probably incorrect in view of 

 all other results. No counts were made, or it would probably have 

 been noticed that some at least of the Fi flies were more like antlered 

 than vestigial. 



Eight Fo mass-cultures were raised (table 57), and these produced 

 a total of 2,901 flies, of which 899 or 31.0 per cent were antlered. On 

 the basis that antlered is completely recessive to vestigial, only 25 

 per cent of the flies should have been antlered; that is, twice (31—25) 

 or 12 per cent of the vestigial-antlered compounds were more like 

 antlered than vestigial. 



An examination of the F2 counts showed that antlered dominated 

 in the males but not in the females. The antlered males comprised 

 44.3 per cent of all the males, which means that at least 38.6 per cent 



Table 58. — Pi, antlered 9 X vestigial d'. 



of the vestigial-antlered compound males were antler-like. Among 

 the females only 20 per cent were antler-like, which probably means 

 that the composition in mass-culture had lowered the percentage of 

 antlered females from 25 to 20, just as in the F 2 from antlered by wild 

 the percentage of antlered was only 19.8. 



The reciprocal cross (antlered 9 X vestigial cf) was started about 

 two months later than the cross just described, and here more attention 

 was paid to the nature of the Fi flies (table 58). 



The relation deduced from the previous F2 was observed in the new 

 Fi ; for while none or only very few of the Fi females were antlered-like, 

 36.9 per cent of the males were antlered. These antlered- vestigial 

 compounds were not typical antlered, but were shorter and very much 

 like strap. 



Six Fi mass-cultures gave in F2 a total of 1,280 females, of which 321 

 or 25.1 per cent were antlered, and 1,270 males, of which 546 or 43.0 



