38 



which the trail is formed, atmospheric conditions, etc., would cause a 

 difference in the length of time a trail could remain unused by the 

 ants and still be recognized. 



An idea of the number of ants passing over the trail in these ex- 

 periments may be gained from the following counts taken at various 

 times. 



January 22. — Between 11:45 '^^'^^ ii-S^j sixty-one ants passed a 

 certain point on the trail, twenty-five going to the food and thirty-six 

 to the nest. 



January 25. — Between 3 :oo and 3 105, ninety-seven ants passed 

 a certain point, sixty-two going to the food and thirty-five to the 

 nest. 



January 26. — Between 9:45 and 9:50, seventy-eight ants passed 

 a certain point, thirty-nine going each way. 



February 2. — Between 1 1 -.t^z and 1 1 :37, seventy-four ants passed 

 a certain point, thirty-six going to the food and thirty-eight to the 

 nest. 



EXPERIMENT NO. 5 



Can ants recognize which direction on the trail leads to the nest? 



Of the seven ants (Experiment 3) placed on the trail from an- 

 other room of the building, three followed it to the food and the 

 other four to the nest. There is here the possibility that three ants 

 sought the food purposely and that four purposely followed the trail 

 to the nest. 



January 28. — 2:45 P-^^- With a camel's hair brush I pick up 

 from the edge of the jar upon which the apparatus is resting today, 

 an ant. No. i, going to the food, and place it on top of the lower disk 

 near the trail. It crosses the trail without seeming to recognize it, goes 

 around the disk once, crosses the trail again, goes half-way around 

 the disk again, and then reaches the stem, where it takes the trail 

 and goes to the food, which it reaches at 2 :5o. 



2 :55 P.M. I take No. 2 from the top disk, going towards the 

 nest, and place it on the lower disk near the trail. It recognizes the 

 trail and after a little hesitation starts towards the food. When it 

 reaches the stem it turns and follows the trail l^ack to the nest. 



3 :o7 P. M. I take No. 3 from the edge of the jar, going to the 

 food, and place it on the lower disk near the trail. It crosses the 

 trail, wanders about for a short time, then strikes the trail and starts 

 to follow it to the nest. It goes over the edge of the disk to the 

 stem, then on past the stem and seems to be lost for a short time, 

 then back to the stem and down it to the edge of the base. There it 



