CROSSINGOVER IN DROSOPHILA 



177 



Interpretation of the tube data 



Control 'curve of age.'' The conclusions to be drawn from the 

 data given in tables 13 and 14, and from its graphic presentation 

 in figuics 4 to 8 can be stated briefly. First, with regard to the 

 percentage of crossingover in the control, our results as given 

 in figure 4, and for a longer period in figures 7and 8 show beyond 



Percentage of 

 crossing over 



Purple-curved 



' Black-purple 



10 12 14 16 18 20 22 24 26 28 30 32 34 3e 



Days 



after mating 



Fig. 4. Control values for both regions from table 13 



Percentage of 

 crossing over 



8 10 12 14 16 18 20 22 24 26 28 30 32 34 3c 



Fig. 5. Curves of percentage of crossingover for both regions shown by the 

 offspring of females hatched at 22° and exposed to 31.5° for the first seven days 

 after hatching (table 13). 



