Turner, Homing of Ants. ' 431 



PLATE III. 



Fig. 8. Learning-curve of an individual Myrmica punctiventris, showing its reactions to colored 

 pathways. 



Apparatus, cardboard stage with a red incline leading down to the island; illuminated by diffuse 

 daylight. 



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



b. Do. Green for red. 



c. Do. Purple for green. 



d. Do. Blue for purple. 



e. Do. Yellow for blue. 

 /. Do. White for yellow. 

 g. Do. Red for white. 



h. Do. White for red. 



/. Do. Smooth black for white. 



k. Do. Black with velvety feel for smooth black. 



Fig. 9. Learning-curve of an individual Formica fusca var. subsericea Say, showing its reactions 

 to odors encountered in its path. 



Apparatus, a cardboard stage with an incline passing down to the island. On this stage the pupae 

 and a marked worker were placed. The worker had made several trips before the first trip plotted here. 



A. While the worker was on the stage, I substituted for the incline one with a transverse band of 

 xylol across its middle. 



B. I replaced the old incline. 



C. While the worker was on the stage I substituted the incline with the transverse band of xylol. 



D. While the worker was on the stage the incline with the xylol band was transferred to the control 

 stage and allowed to remain there eight minutes. The ant used for control was much disturbed. Dur- 

 ing the eight minutes it mounted the incline several times, but would not cross the band. 



E. The incline with the xylol band is reattached to stage i. During the eight minutes that have 

 elapsed the marked ant has made several trips down an unscented incline which was attached to the stage 

 when the incline scented with xylol was removed. 



F. The incline with the xylol band is transferred to the control stage and causes the same disturb- 

 ance as before. 



Fig. 10. Learning-curve of a Myrmica punctiventris, showing its reactions to light rays and to 

 tactile stimuli. 



Apparatus, a cardboard stage with an incline A passing from left side to the island. Near the left 

 side of the stage was placed a i6 c.p. incandescent lamp. The room was darkened. 



a. While the worker was on the stage the i6 c.p. lamp was transferred to the right side of the stage. 



h. While the worker was on the stage, the incandescent lamp was extinguished and the curtain of a 

 window thrown up so as to illuminate strongly the left side with daylight. 



c-d. Experiment was interrupted for six minutes. 



d. The same stage, but illuminated uniformly by diffuse daylight instead of by an incandescent 

 lamp in a special position. A smooth black incline leads from the stage to the island. 



e. While the worker was on the stage the white incline was substituted for the black. 

 /. Do. Smooth black incline for white. 



g. Do. Black incline with velvety feel for the smooth black. 



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

 to a colored pathway. 



Apparatus, a cardboard stage with red incline leading down to island, illuminated with diffuse day- 

 light. 



a. While the worker was on the stage a new red incline was substituted for the old. The paper on 

 this incline was somewhat wrinkled. 



h. Do. Green for red. 



Fig. 12. Learning-curve of an individual Formica fusca var. subsericea Say, showing effect of a 

 jar upon its behavior, etc. 



Apparatus, a cardboard stage with a white incline leading from its right side to the island. A heat- 

 filter composed of a tall rectangular museum jar filled with water was placed near both the right and 



