308 PROCEEDINGS OF THE ACADEMY OF [Apr., 



these mutilated hornets were placed into the experimental cases, 

 they were at first extremely restless, then they became "sullen" 

 and inactive. 



Some of these mutilated hornets responded promptly when tested 

 with the three essential oils; some responded slowly, and a few 

 failed to respond at all. All of those which failed to respond to 

 odors scarcely moved when touched with a pencil. These were 

 discarded and the flagella of others were cut off. In behavior, hornets 

 with the flagella cut off are abnormal, and these lived from 3 hours 

 to 3 days and 20 hours with 1 day and 13 hours as an average. The 

 reaction times are: oil of peppermint, 2-5 seconds, average 2.84 

 seconds; oil of thyme, 2-5 seconds, average 2.92 seconds; oil of 

 wintergreen 2-5 seconds, average 3.52 seconds. These give a 

 general average of 3.09 seconds which is 0.66 second greater than the 

 same average for normal hornets. We can certainly attribute this 

 small difference in reaction time to the inactiveness of the mutilated 

 insects. 



III. Summary. 



The common response of all the normal ants tested to each of the 

 six odors used is as follows: (1) if lying flat on the thorax and 

 abdomen, they arose either slowly or quickly; (2) if standing on their 

 feet, they moved away either slowly or quickly. The more common 

 response is — they vibrated the antennae and moved away either 

 slowly or quickly. The most common response is — they vibrated 

 the antennae more or less vigorously. Many of the ants turned 

 around over the odors. While testing with honey and formic acid, 

 many of the ants tried to get through the bottoms of the cases to 

 the sources of the odors. In one instance while testing with formic 

 acid, the ant turned up its abdomen in the same position in which 

 the abdomen is held when the ant attacks an enemy. The average 

 reaction times of all six odors for all the normal ants tested in any 

 one set of experiments are as follows: females of Formica 2.45 seconds, 

 males of Formica 2.63 seconds, males of Camponotus 2.74 seconds, 

 major workers of Camponotus 3.22 seconds, and minor workers of 

 Camponotus 3.09 seconds. The average reaction time of the three 

 essential oils for all the normal hornets tested is 2.43 seconds. From 

 these figures, it is evident that the olfactory sense in the ants and 

 hornets tested is quite acute. Judging from the reaction times of 

 the females and males of Formica, the olfactory sense in both sexes 

 is equally developed. The slightly slower reaction time of the 



