304 PROCEEDINGS OF THE ACADEMY OF [Apr., 



Formic acid: 



10 moved quickly and tried to get at odor. 

 6 vibrated antennae. 



3 vibrated antennae and turned around over odor. 

 2 vibrated antennae and tried to get at odor. 

 2 moved away and vibrated antennae. 

 1 jumped toward source of odor. 

 1 moved away slowly. 



Reaction time 2-6 seconds, average 3.40 seconds. 



The average reaction time of all six odors for the 25 large workers 

 tested is 3.22 seconds. These ants were kept in a Fielde nest with 

 many more workers and males. Between May 24 and July 5, 19 

 workers of various sizes had died. These 19 lived from 47 to 72 

 days, with 26 days and 8 hours as an average. 



5. Minor Workers of Camponotus. 



To ascertain if the smallest workers of a colony of ants respond 

 as quickly to odor stimuli as do the largest workers of the same 

 colony, 25 small workers were tested. These were sisters to the 

 large workers just described and were taken from the same colony. 

 The responses of the small workers to the six odors were similar to 

 those of the large workers. In two instances when the ant was 

 tested with honey and comb, it tried to get at the source of the odor. 

 In one instance when the ant was tested with formic acid, it turned 

 around quickly and turned up the abdomen as if going to discharge 

 its own formic acid. 



The reaction times for the 25 small workers are: oil of peppermint, 

 2-3 seconds, average 2.12 seconds; oil of thyme, 2-3 seconds, average 

 2.08 seconds; oil of wintergreen, 2-4: seconds, average 2.60 seconds; 

 honey and comb, 2-10 seconds, average 4.84 seconds; leaves and 

 stems of pennyroyal, 2-5 seconds, average 3.16 seconds; formic 

 acid, 2-8 seconds, average 3.72 seconds. The average reaction time 

 of all six odors for the 25 small workers tested is 3.09 seconds. 



Only 2 soldiers were tested. They were sisters to the workers 

 just described. Their reaction times are similar to those of the 

 other workers. 



6. Females of Vesjnda maculata. 



A large hornets' (Vespula maculata) nest, containing many adult 

 hornets and all stages of young, was suspended inside a large wire- 

 screen cage. Twenty-five of the adult worker hornets were removed 

 from the cage, and they were then placed singly into the experimental 



