23 



center of the base, and this was filled with cement in a way to make 

 a disk which, being in contact with the water beneath, was always 

 moist. In these cages the orange cover was a circle of glass 3^2 

 inches in diameter. 



The fluid repellents were commonly applied by saturating fine 

 sand with them and depositing this in a small pile at the center of the 

 nest. This was always done after the ant colony with its larvae in 

 charge had established itself beneath the orange cover. 



The object of these experiments being merely to test the sub- 

 stances in a comparative way, the conditions were in all cases made 

 as nearly identical as practicable, especially with respect to heat and 

 light. It is nevertheless evident that they are subject to the disadvan- 

 tage that colonies of ants of the same species are not necessarily equal 

 and similar in their reactions, and that the same colony may not al- 

 ways react in the same way to the same treatment. One of the most 

 interesting of Mr. Tanquary's observations shows that the aspect of 

 the reaction may be considerably changed by the exceptional sensibil- 

 ity or activity of only a very few of the individual ants of a family 

 group — only three or four, perhaps, out of as many hundred rising to 

 the occasion and rescuing the young from dangerous or offensive situ- 

 ations. 



I have found no way of tabulating or otherwise condensing the 

 descriptions of Mr. Tanquary's notes, and can only give the main re- 

 sults of the tests in very general terms, referring the reader for fur- 

 ther information to the details of the observations. Generally speak- 

 ing, then, it seems from these experiments that oil of tansy, oil of 

 lemon, anise oil, tincture of asafetida, apterite, and vermicide are very 

 strongly repellent to the corn-field ant; that kerosene, camphor, and 

 coal-tar are strong repellents, and that the other substances tested are, 

 if repellent at all, too slightly so, or for too short a time, to make them 

 promising materials for any practical use. 



Experiment 5768^, Check. — January 13, 10:25 a. m., as a check 

 upon the other experiments, a little sand moistened with water was put 

 under an orange cover which had been removed for this purpose to a 

 fresh part of the base at the close of an experiment with oil of lemon. 

 The ants immediately began to assemble under the cover, carrying 

 their larvae with them; but twenty-seven of the latter were thrown by 

 their nurses into the water, probably because they still smelled of the 

 lemon oil. Other ants began at once to carry out the sand grains and 



* The numbers here used are those of the "experiment record" of the office, 

 a book in which all experiments are permanently recorded. 



