36 



ing from the nest. The larvae, which were four-eighths of an inch 

 from the sand, were deserted (Fig. 13, A). At 11 o'clock about 

 one-third of the ants were in the nest, as shown in the figure, the near- 

 est of them five-eighths of an inch from the repellent. At 11 : 15 a. m., 

 1 : 30 and 2 : 25 p. m.- — 3 hours, 50 minutes — the nest presented practi- 

 cally the same appearance. At 3:45 (5 hours, 10 minutes), nearly all 

 of the ants had left the nest and a few of the larvae had been carried 

 to its outer edge (Fig. 13, B). At 4: 45 and at 5 : 50—7 hours, 15 min- 

 utes — about a dozen ants were still in the nest. April 21, at 9:30 

 a. m., no ants were in the nest, the larvae having all been carried out- 

 side. At 11 : 30 (24 hours, 55 minutes), several ants had moved under 

 the cover as shown in the sketch. At 3 : 30 and 5 p. m. the situation 

 was unchanged. By 8: 20 a. m. April 22 (45 hours, 45 minutes), about 

 three-fourths of the ants were in the nest, filling it half way; at 11 

 a. m. (48 hours, 25 minutes) the situation was unchanged, and the 

 experiment was closed. 



Experiment 5758, Formic Acid.- — January 14, at 10: 30, a small lot 

 of sand mixed with formic acid was placed on the base, and the orange 

 cover was moved over it to form a nest with the repellent at its center. 

 The ants presently began to move into the nest, but were immediately 

 affected by the odor of the acid. Only two approached the sand near 

 enough to touch it, and these jerked quickly back, vigorously rubbing 

 their antenna?, which had been brought in contact with the acid. At 

 10:45 the ([ueen of the colony entered the nest and the workers were 

 moving their larvas, all keeping as close to the borders of the nest as 

 practicable, the innermost of the assembly being always restless and 

 active. At 11:30 and at 11 : 55 (1 hour, 25 minutes), the ants were 

 clustered at each of the four corners of the cover. At 3 :10 p. m. (4 

 hours, 40 minutes), nearly all the ants were in the nest, a few nearer 

 the sand than before, the nearest within two-eighths to three-eighths 

 of an inch. Some occasionally crossed the clear space within the cir- 

 cle, and occasionally one even crawled over the sand, seeminglv un- 

 aft'ected by its odor. By 8:10 the next morning the ants were paying 

 no attention whatever to the sand, which was removed. It had not 

 the slightest perceptible odor, formic acid being highly volatile. 



The experiment was repeated at 8:20 a. m. of this day, January 

 15, the ants immediately scattering, about one-third of them retreat- 

 ing to a corner of the base. At 8: 35 the ants were collected in two of 

 the corners of the nest, the queen among them, and under the edge of 

 the, ^j;q\j^r .farthest from the repellent, the nearest an inch and an 



