DO ANTS FORM PRACTICAL JUDGMENTS? 34 1 



antennae. When this condition of calm had been attained, which 

 usually required about five minutes, the glass cone was quietly 

 removed. Thus the confining cone was not removed until the 

 ant had recovered from the excitement caused by the handling. 1 

 Now if contact with crack e or the odors ascending through it 

 will induce ants refiexly to cover it with trash, then, when free to 

 roam at large, the ant should have proceeded to cover the crack 

 with trash. This was tried with twelve different ants, but in no 

 case did the ant cover the crack with trash. In all cases the ant 

 carefully examined the crack and in one case it tried to force its 

 way through the crack into the nest. Sooner or later the ant 

 would begin to roam about over the top of the nest and in some 

 cases over the Lubbock island as well. After awhile it would 

 enter the nest. Some ants entered the nest within a minute after 

 the confining cone was removed, one spent two hours finding its 

 way home, one became lost and the majority took less than 

 three minutes to find the entrance to the nest. About an hour 

 after the beginning of the experiment an unmarked worker from 

 the nest began to cover the crack with trash, and by the close of 

 the third day it had covered cracks e and b in the usual manner 

 (Fig. 2). 



Once or twice a week for several months I continued to re- 

 move the trash from crack e, soon after it had been completely 

 covered. Each time the crack was recovered. On June 28, 

 however, the ants not only covered the top of e with trash, 

 but beneath e, on the inside, they built up a wall of detritus, 

 through which a tunnel connected the two halves of compartment 

 C. The outside cover was composed of a heterogeneous mass 

 of coarse particles of various kinds and a few cotton fibers ; the 

 partition constructed on the inside consisted of a felted mass of 

 cotton fibers and fine crumbs of bread. Nine times I destroyed 

 this inner portion ; each time it was reconstructed by the ants out 

 of the same kind of material. The tunnel through the partition 

 was sometimes located in one position and sometimes in another. 

 The different partitions varied in width from one fourth to three 



1 Experiments recorded in my paper on "The Homing of Ants" show that the 

 handling of ants to mark them with water colors does not alter their physiological 

 attunement. 



