200 JOHN L. PRICER. 



Experiment I. 



January i, igoy'. — On one side of the hall glasses were 

 placed on the rooms in the following order : red, orange, green, 

 indigo, blue, clear ; and on the other side in the reverse order, so 

 that the two red glasses were on diagonally opposite corners of 

 the nest. A colony of C. pennsylv aniens was introduced into the 

 feeding-room. This colony was just large enough to fill com- 

 fortably two of the rooms, and too large to get into one. 



January 2. — All ants were settled in the two rooms covered 

 by red glass. The red plates were now exchanged with the two 

 clear plates, and on January 3, all ants were again collected under 

 the red glass. These red plates were now removed from the nest 

 and were replaced by plates of clear glass. On January 4, about 

 one third of the colony were in one room under green glass, 

 another third were under orange, and the remaining third stayed 

 where they were under clear glass for four days, finally joining 

 their companions under the green and orange respectively on 

 January 8. These glasses were now exchanged with the two 

 indigoes, and the ants remained unsettled for a whole week of 

 dark, cloudy weather, as many of them remaining under clear 

 glass as under any other. On January 15, I placed double 

 thicknesses of orange glass over two of the rooms, and on Janu- 

 ary 18 all ants were collected in these two rooms. I now 

 removed the orange glasses from the nest, replacing them with 

 clear glass, and on January 19, after a few hours of bright sun- 

 shine, the ants were all collected under the two green glasses. 

 These were then exchanged with clear glass and the ants were 

 again unsettled for a period of six days, when a bright day caused 

 them to settle under the green glasses on January 25. These 

 glasses were now removed from the nest and replaced by clear 

 glass. The nest was then left for twelve days in this condition 

 with only the blue, indigo and clear glass over the rooms, and 

 although there were several bright days during the time, the 

 ants never settled in any one room, but seemed to be endeavoring 

 to escape. On February 6 I replaced two of the clear plates 

 with the two green plates, and on February 8 all ants were col- 

 lected in these rooms. I then placed the orange plates back on 

 the nest, but no ants collected under them. On February 15 I 



