Turner, Homing of Ants. 427 



1;. Do. 3:40 p.m. Same apparatus as above, only I added incline B to the right side of stage, so 

 that now incline A is on the left and incline B on the right. The ants carried the pupae down A, none 

 were carried down B. 



6. Do. 3:58 p.m. Same apparatus as above. The ants had rested seventeen minutes. 



7. Do. 4:20 p.m. Same apparatus as before, only inclines yf and £ were made to change places. 

 All the pupae were carried down B, none were carried down the scented incline A. The ants had rested 

 one minute. 



8. Do. 4:40 p.m. Same apparatus as above. No pupae carried down A. The ants had rested 

 one minute. 



9. Do. 5:06 p.m. Same apparatus as above. The ants had rested one minute. 



10. June 26, 7:12 a.m Same apparatus as above. All the pupse were carried down B, a few 

 unburdened workers occasionally promenaded on A. The ants had rested one day, thirteen hours and 

 forty-nine minutes. 



11. Do. 7:42 a.m. Used the same stage but turned it bottom side up, thus making practically a 

 new stage. The same inclines were used in the same position, A on the right and B on the left. All the 

 pupae were carried down B, none were carried down A. The ants had rested two minutes. (An unbur- 

 dened worker went down B to the nest one minute after the ants were placed on the stage.) 



12. June 26, 8:11 a.m. Same stage, but inclines A and B are both removed and a new incline 

 C placed where A had been; this left no incline at the place where the ants had been descending and an 

 unscented incline on the other side. The ants pick up pupae and go immediately to the place where B 

 had been. Failing to find B, they become much confused. They return over and over again to that 

 point and reach down as though hunting for something. Finally they carry the pupae down C to the 

 nest. The ants had rested twenty-nine minutes. 



13. Do. 9:42 a.m. Same apparatus as above. Several workers convey pupae to where B had 

 been. The ants had rested two minutes. 



14. Do. 10:09 ^-ni' Same apparatus as above. The ants had rested two minutes. 



15. Do. 10:30 a.m. Same apparatus as above. The ants had rested one minute. 



16. Do. 11:02 a.m. Same apparatus as above, only I added a new incline Z) to the left side of the 

 stage. The majority of the pupae were carried down C; only two pupae were carried down D. The ants 

 had rested four minutes. 



17. Do. 1 1 :24 a.m. Same apparatus as before, only C and D were interchanged, so that we now 

 had the unscented path D in the path the ants had been traversing. The majority of the pupae were 

 carried down D, only three were carried down C. The ants had rested nine minutes. 



18. Do. 6:55 p.m. Same apparatus as above. The ants had rested one hour and two minutes. 



19. Do. 7:18 p.m. Same stage, but I replaced C by D and placed a new incline E where D had 

 been. The majority of the pupae were carried down D. The ants had rested two minutes. 



Fi G. 3 . Learning-curve of Prenolepis imparis acting in concert, showing lapse of memory, the effect 

 of light rays, interruptions of the path, etc. 



I. June 27, 9:42 a.m. A new cardboard stage with new incline A descending from its left side to 

 the island. 



Same apparatus as above. The ants had rested two minutes. 

 Same apparatus as above. The ants had rested one minute. 

 Same apparatus as above. The ants had rested thirty-five minutes. 

 Same apparatus as before, only there is a vertical gap of i mm. between the 

 foot of the incline and the island. The ants had rested four minutes. 



6. Do. 1:15 p.m. Same apparatus as before, but the vertical gap is increased to 4 mm. The 

 ants had rested ten minutes (see text, p. 410). 



7. Do. 2:35 p.m. Same apparatus as before, only the 4 mm. gap was horizontal instead of verti- 

 cal. The ants had rested forty-two minutes. 



8. June 28, 10:55 ^•"'* Same apparatus as before only the ants must cross a horizontal gap of 4 

 mm. to a pile of slides and down them to the island. The delay was caused by the gap. They went 

 down to the gap and there hesitated, many returning to the stage. This was unexpected, since only 

 yesterday they had been trained to cross a horizontal gap of that kind. The ants had rested twenty- 

 two hours and twenty minutes. 



9. July 10, 7:16 a.m. A cardboard stage from which an incline ascends to the nest. The ants had 

 rested thirteen days, twenty hours and eleven minutes. 



10. Do. 7:55 a.m. Same as above. The pupae had rested four minutes. 



11. Do. 8:46 a.m. Used same stage and incline but rotated the stage through 180°. Incline 

 in same position. This gave an unscented path from pupae to the incline. The ants went direct to 

 the incline. The ants had rested one minute. 



