CROSSINGOVER IN DROSOPHILA 



183 



TABLE 16 

 b pr c 



Control, hatched and mated at 22°C. Nos. 660-664 



March 29 



March 31 



April 2 



April 4 



April 7 



April 9 



April 11 



Hatched, 22°C. 



48 

 109 

 113 



108 

 84 

 52 

 50 



Exposed to 31.5°C. from second to fourth day after mating. 

 Nos. 665-669 



Hatched, 22°C. Exposed to, 31.5°C. from second to sixth day after mating. 



Nos. 675-679 



March 29 

 March 31 



April 2. 

 April 4. 

 April 7. 

 April 9. 

 April 11. 



38 

 62 

 43 

 82 

 78 

 68 

 68 



12l for the disappearance of the effect after heat was removed in 

 figure 5 results from the fact that one two day count (November 

 17 in table 13) failed entirely, resulting in a loss of about one hun- 

 dred flies from the total. The items in the first column of Nos. 3 

 and 4 (table 15) are probably slightly lower than the actual num- 



