622 PROCEEDINGS OF THE ACADEMY OF [Sept., 



Experiment 19. — Time, 22 days. 



Single orange pane, transmitting red, orange, yellow, green, blue. 



Single yellow pane, transmitting red, orange, yellow, green, 

 blue, indigo. 



The ants moved once to the orange side, and afterward stayed 

 conseculive days under each pane. Interchanges of the panes 

 never caused a removal of the ant-group. The ants have, then, 

 but slight dislike for the indigo rays, the only rays in which the 

 sides of the cell differed. 



Experiment 20. — Time, 65 days. 



Orange pane, transmitting red, orange, yellow, green, blue. 



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

 violet. 



The ants removed hastily from under the violet as often as inter- 

 change of the panes was made, one or twice a day, for about 

 twenty days. Thereafter they became indifferent to the violet 

 rays. Their' action indicates instinctive fear of the short w'ave- 

 length rays, a fear that subsides with experience. 



Experiment 21. — Time, 50 days. 



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



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

 violet. 



The ants withdrew in haste from under the blue pane. 1 

 interchanged the glasses once or twice a day, and their removal 

 from under the blue pane was speedily made, until about twenty 

 days had elapsed, when they became dilatory in their removals 

 and remained sometimes several days under the blue pane. 



Experiment 22. — Time, 40 days. 



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



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

 violet. 



The ants removed from under the violet pane and settled under 

 the green pane as often as I interchanged the panes, once or twice 

 a day, up to the twenty-fifth day, when they became dilatory and 

 manifested increasing indifference to their roofing. The red rays 

 did not neutralize the effect of the violet ones. 



An analysis of the results of these experiments shows that the 

 ants manifested no liking for any of the rays of light. If obliged 

 to stay in light rays of some sort, the rays of longer wave-length 



