Turner, Homing of Ants. 409 



rare phenomena in the confines of the nest. With ants, as with 

 us, it seems that unusual stimuh cause unrest. 



Experiments on Direction and Distance. — Lubbock ('81, p. 260) 

 devised an experiment which shows that ants have accurate 

 impressions of direction in a horizontal plane. This experiment, 

 a portion of which I shall presently quote, has been repeated by 

 me, with confirmatory results, on most of our southern species of 

 ants. Lubbock writes as follows,"! then accustomed some ants 

 (Lasius niger) to go to and fro over a wooden bridge, b,c, to some 

 food. When they had got quite accustomed to the way, I watched 

 when an ant was on the bridge and then turned it around, so that 

 the end b was at c, and c at b. In most cases the ant immediately 

 turned around also; but even if she went on to b or c, as the case 

 may be, as soon as she came to the end of the bridge she turned 

 around. I then modified the arrangement, placing between the 

 nest and the food three similar pieces of wood. Then when the 

 ant was on the middle piece, I transposed the other two. To my 

 surprise this did not at all disconcert them." 



Lubbock next tried a different experiment. By means of a 

 pin through its center, he pivoted a disk of cardboard to the middle 

 of the table. At one corner of the table he placed some food. 

 When the ants had come to know their way so that they passed 

 straight over the paper disk on their way from the nest to the 

 food, he moved the disk around with an ant on it, so that the side 

 that had been towards the nest was now towards the food. As 

 in the above experiment, the ants turned round with the paper. 

 He also repeated it with a table arranged to revolve in three 

 concentric sections. The result was the same as above. 



I think some of my experiments warrant the assertion that ants 

 have an impression of vertical as well as horizontal direction. 



In my experiments (excepting those on color and tactile phenom- 

 ena) the stage and incline were made out of the same material, 

 often being cut from the same piece of cardboard. The apparatus 

 was so adjusted that when the ant reached the union of stage with 

 incline, only two changes in movement were necessary in order 

 to take the next lap of the journey; the ant must turn so as to 

 receive the light rays on a different side than before, and it must 

 move obliquely downward instead of moving in a horizontal 

 plane. The apparatus was also so adjusted that if the ant turned at 

 the parting of the ways and moved horizontally along the stage in 



