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Wasmaxn', E. 



'91. Zur Frage nach dem Gehorsvermogen der Ameisen. Bio!. Centralbl., Bd. 11, pp. 26-27. 

 Watson, Jno. B. 



'03. Animal Education. Univ. oj Chicago Press. 

 Weld, Le Roy. 



'99. The Sense of Hearing in Ants. Science, n. s., vol. 10, pp. 766-768. 

 Wroughton, Robert. 



'92. Our Ants. Joi^r. Bombay Nat. Hist. Soc. 

 YerkeSjR. M. 



'03. The Instincts, Habits and Reactions of the Frog. Psychological Review. Monog. Suppl. 

 no. 17; Harvard Psychological Studies, vol. I. 



EXPLANATION OF FIGURES. 



In all of the figures the successive ordinates represent minutes of time. In Figs, i to 6 (see text, p- 

 382) each abscissa represents an experiment in the series tabulated and each ordinate the time in minutes 

 that elapsed in that case from the beginning of the series until the first pupa was carried to the nest. 

 These experiments were conducted on ants acting in concert, the purpose being to see if ants retain what 

 they gain by experience. In the remainder of the figures the abscissae represent successive trips to the 

 nest. When a line terminates in an arrowhead, that indicates a failure. In all curves any time less than 

 a quarter of a minute is considered zero. 



PLATE II. 



Fig. I. Learning curve of Myrmica punctiventris Rog., acting in concert, showing how easily it 

 is affected by even slight changes in the environment, and that it has not a homing instinct. 



1. June 21, 7:30 a.m. Apparatus, a cardboard stage connected on the right to the island by 

 means of a cardboard incline {A). 



2. Do. 2:45 p.m. Same apparatus as' before. The ants have had a rest of two hours and thirty- 

 five minutes. 



3. June 22, 11:08 a.m. Same apparatus as before. The ants have had a rest of twenty hours 

 and twenty-three minutes. 



4. Do. 2:35 p.m. Same apparatus as before. The ants have had a rest of one minute. 



5. 3:56 p.m. Same apparatus as above. The ants have had a rest of twenty-six minutes. 



6. Do. 4:48 p.m. Same stage as before, but the scented incline is placed on the left side of the 

 stage and a new unscented incline {B) placed where the scented incline had been. The pupae were all 

 carried down the new incline. No larvae were carried down the old incline; one worker started down the 

 old incline and then returned to the stage. Occasionally, a worker would ascend the old incline from 

 the island. The ants had rested one minute. 



7. June 23, 10:40 a.m. Same apparatus as before. Workers carry the pupae down incline J5 to 

 the nest; other workers convey pupae down incline A and store them under its foot, thence stragglers 

 from the nest convey them to the nest. The ants had rested twenty-nine hours. 



8. July II, 9:15 a.m. A new cardboard stage, a new incline and all (even the nest) was placed on 

 a new island. The figure indicates a failure but does not indicate how great. Those ants were lost for 

 over twelve hours. At 9:50 p.m. when I left the laboratory, they were resting quietly on the stage. 

 Sometime before 8:30 the next morning they found the way to the nest (see text, p. 379). 



9. July 13, 7:54 a.m. Same apparatus as above. The ants had rested a day and had had a 

 chance to become acquainted with the island. 



10. July 24, 9:15 a.m. A cardboard stage from which one incline passed to the island. A dark 

 chamber opening upon the stage and also upon the incline, was placed over the top of the incline. All 

 the pupae were stored under the dark chamber, none were carried to the nest. The workers went to 

 the nest and left the pupae on the stage. The ants had rested eleven days and seventy-four minutes. 



Fig. 2. Learning-curve of Prenolepis imparis Say, showing that the homing of ants is not a chemo- 

 tropism and that ants can learn a new way home when the way they once knew has been removed. 



1. June 24, 7:38 a.m. A new cardboard stage with a new incline (A) attached to the left side. 



2. Do. 2:46 p.m. Same apparatus as above. The ants had rested three hours and forty-six 

 minutes. 



3. Do. 3:10 p.m. Same apparatus as above. The ants had rested ten minutes. 



4. Do. 3:20 p.m. Same apparatus as above. The ants had rested four minutes. 



