Turner, Homing of A tits. 433 



PLATE IV. 



Fig. 14. Learning-curve of an individual Formica fusca var. subsericea Say, illustrating its reaction 

 to changes in the direction of light, to colored pathways, and to tactile stimuli. 



Apparatus, a cardboard stage with a white incline leading from the right side to the island. A l6 c.p. 

 lamp is placed on the same side of the stage as the incline. Throughout the whole of this part of the 

 experiment the worker ascended to the stage on the top side of the incline, and descended to the island 

 on the lower side. 



A. Placed a new white incline on the side opposite the old incline. 



B. While the worker was on the stage, the 1 6 c.p. was transferred to the opposite side of the stage. 



C. Replaced the light on the same side as the incline. 



D. While the worker was on the stage, I transferred the light to the opposite side of the stage. 



E. I replaced the light in former location. 



F. While the worker was on the stage, I substituted a smooth black for the white incline. 

 G-H. The experiment was interrupted from 7:41 p.m. to 8:41 a.m. 



H. The same stage, but a red incline is substituted for the white and no artificial light is used. 

 In this section of the experiment the worker goes in almost a straight line from the foot of the incline to 

 the side of the nest and then to either the right or the left (for it does not always follow the same line) 

 to the nest; but in returning to the incline it meanders a great deal. 



/. While the worker was on the stage, I substituted a new red incline for the old red one. 



A'. While the worker was in the nest, a green incline was substituted for the red. 



L. While the worker was on the stage, a purple incline was substituted for the green. 



M. While the worker was on the stage, I substituted a yellow for the purple incline. 



N. While the worker was on the stage, a blue incline was substituted for the yellow. 



0. While the worker was on the stage, a smooth black incline was substituted for the yellow. 



P. While the worker was on the stage, a black incline with velvety feel was substituted for the 

 smooth black. 



Fig. 15. Learning-curve of an individual Myrmica punctiventris, showing its reactions to colored 

 pathways, etc. 



Apparatus, a cardboard stage with an inclined plane leading down to the island. Illumination, 

 diffuse daylight. During the first twenty-three trips the pupae were carried only so far as the base of the 

 incline; from there other workers conveyed them to the nest. 



A. While the worker was on the stage a new white incline was substituted for the old. 



Smooth black for white. 



Black with velvety feel for smooth black. 



Red for black. 



Green for red. 



Purple for green. 



Yellow for purple. 



Blue for yellow. 



White for blue; placed a 16 c.p incandescent lamp on the same side of stage as the incline 

 and darkened the room. 



Fig. 16. Learning-curve of an individual Formica fusca var. subsericea Say, showing the effect upon 

 its behavior of a change in the direction of the light rays. 



Apparatus, cardboard stage with incline descending to the island. 



A. Between 24 and 25 the experiment was suspended for one hour. 



B. Between 49 and 50 the experiment was suspended for four hours and twenty-six minutes. 

 From B to C the ant was working at night by lamplight and the direction of the rays was from the 



northeast. The rest of the work was done by daylight and the direction of the rays of light was from 

 the south and west (see p. 400). 



C. Between 66 and 67 the experiment was suspended for eleven hours and twenty-six minutes. 



Fig. 17. Learning-curve of an individual Formica fusca var. subsericea Say, showing its reactions 

 to changes in the direction of the rays of light. 



Apparatus, a cardboard stage with a white incline leading from the right side to the island. A 4 c.p. 

 incandescent lamp was placed near the right side of the stage; otherwise the room was dark. 



A. While the worker was on the stage, I substituted a 32 c.p. lamp for the 4 c.p. 



B. While the worker was on the stage, I transferred the 32 c.p. to the left side of the stage. 



