RELATION OF BURSARIA TO FOOD 



35 



MIXTURE, DISH A 



TABLE 18 (b) 

 Experiment XVI (b) 



NUMBER OF GRAINS EATEN' BY EACH INDIVIDUAL 



Stained.. . . 

 Unstained . 

 Control, 



Dish B 

 Unstained. 





 



16 



17 





 1 1 



131011 



12 



Oj 



2 



512 



12 



15 



15 







d 1 



16 



10 



13 







19 



216 



the count. The smaller number of grains eaten in (b) by those 

 in dish A is due in part to the shorter time of feeding but more 

 to the fact that the unstained yolk grains had by this time ad- 

 sorbed some of the liberated janus green fro'm the stained yolk 

 grains (see Experiment XVIII, p. 36). 



Experiment XVII (a) and (6). The results of this experiment are 

 given to show that Bursariae from two different cultures may show 

 different reactions in selection experiments. In part (a) material was 

 used from one wild culture, while in part (b) material from a differ- 

 ent one was used. Both were starved twenty-four hours before using 

 them. All other conditions were ahke. Time of feeding fifteen minutes 

 (table 19). 



TABLE 19 

 Experiment XVII 



MIXTURE, DISH A 



Stained 



Unstained 



Control: dish B, 

 Unstained 



Stained 



Unstained 



Control: dish B, 

 Unstained 



NUMBER OF GRAINS EATEN BY EACH INDIVIDUAL 



0| 



01 4 



5 4 





 ol 1 







1 1 



3 3 







o! 





 9 



99 



(a) 







7 9 



410 





 5 



1! 6 





 70 



148 



(b) 



In such experiments as these it was found that occasionally an 

 individual had eaten a stained grain along with the unstained 

 ones, but this happened very seldom in any of the experiments 

 with janus green. 



