1902.] NATURAL SCIENCES OF PHILADELPHIA. 619 



paues were many times interchanged, but the interchange never 

 caused their removal to the other side of the cell. The red and 

 green rays were evidently as acceptable to them as were the red 

 rays alone. 



Experiment ^.— Time, 53 days. 



Yellow pane, transmitting red, orange, yellow, green, blue, 

 indigo. 



Green pane, transmitting orange, yellow, green, blue, indigo. 

 The ants stayed indifferently through consecutive days under 

 either pane, never removing from one side of the cell to the other 

 on account of an interchange of the panes. They have therefore 

 no preference for the red rays transmitted by the yellow pane. 

 Experiment 5.— Time, 50 days. 

 Red pane, transmitting red only. 



Yellow pane, transmitting red, orange, yellow, green, blue, mdigo. 

 The ants removed five times from under the yeUow pane to the 

 red ; but were dilatory in their removals. They once waited three 

 days, once four days, and once seven days, before removing. 

 Experiment 6. — Time, 20 days. 



Yellow pane, transmitting red, orange, yellow, greeu, blue, indigo. 

 Blue pane, transmitting orange, yellow, green, blue, indigo, 

 violet. 



The ants always removed from under the blue pane within a few 

 minutes after it was put over them. I interchanged the panes once 

 or twice a day. In the first ten days they removed 20 times to the 

 yellow side. The cause of the movement must have been either 

 preference for the red or avoidance of the violet, and that the latter 

 was the cause is indicated by Experiment 4. 

 Experiment 7.— Time, 21 days. 



Indigo pane, transmitting yellow, green, blue, indigo, violet.^ 

 Violet pane, transmitting red, orange, yellow, greeu, blue, indigo, 

 violet. 



The ants removed five times from under the violet pane to the 

 indigo side of the cell, but their movements were dilatory, and they 

 stayed, toward the end of their sojourn, six consecutive days under 

 the indigo pane, and then six consecutive days under the violet 

 pane. This indicates lack of preference for the red and orange 

 rays transmitted by th'e violet pane. The violet pane transmitted 

 more of the violet rays than did the indigo pane. 



