80 THE ARGENTINE ANT. 



1 to 2 inches wide and thick enough to obscure entirely the bottom of 

 the pan. This arrangement was made at 2 p. m., and by 5 p. m. the 

 ants were crossing the tobacco dust and getting the honey with as 

 much faciUty as they would have crossed an equal amount of soft dirt. 

 The experiment was repeated, finely powdered sulphur being substi- 

 tuted for the tobacco. The sulphur was not crossed so quickly as the 

 tobacco dust, but within 24 hours the ants were crossing it freely. 

 On one occasion the senior author planted a small lettuce bed, and 

 thinking to protect the seeds until they germinated, he spread over 

 the surface of the bed a layer of tobacco dust covered in turn by a 

 layer of powdered sulphur. The ants got the seeds. 



Tree tanglefoot, when placed about the trunks of trees up which 

 the ants were traveling, checked them for periods var3"ing from a few 

 hours to three or four days. However, a more ddute form of this 

 material, used with much success in the gipsy moth work in ^lassa- 

 chusetts by ]\Ii\ D. jM. Rogers, has recently been tested by the junior 

 author with the result that in one case it kept the ants off the trees for 

 as much as two weeks without being renewed. There is therefore a 

 possibility that this special form of tanglefoot may have a use in the 

 protection of trees. 



Kerosene acts as a repellent until the odor has largely disappeared, 

 but a film of kerosene on water only affords a good floor for the ants 

 to travel on. 



Various devices in the form of inverted troughs of tin or other 

 smooth surfaces have been tried without success. 



Crude petroleum, of all the liquids tested, has proved to be the 

 most effective repellent. When placed in dishes supporting the legs 

 of tables, benches, etc., it will continue to repel the ants even after a 

 great amount of dust and trash has accumulated in it. Its use 

 indoors, owing to its oily nature and disagreeable odor, is of course 

 impracticable. Out of doors it is useful for giving temporary pro- 

 tection to such food materials as sugars, molasses, honey, etc. 



CORROSIVE SUBLIMATE AND "ANT TAPES." 



The only repellent found to possess any merit (aside from sweetened 

 arsenical solutions, described below) was dry corrosive subUmate. 

 Woodwork or cloth which has been treated with a saturated water 

 solution of corrosive subUmate and allowed to dry will not be crossed 

 by the ants while any of the sublimate remains. This fact is utilized 

 in a practical way by soaking ordinary cotton tape about 1 inch wide 

 in the corrosive sublimate solution, wringing it out, and then dr3'ing 

 it. When this " ant tape" is fastened around the logs of tables, edges 

 of shelves, etc., the ants will not cross it for many months, })rovided 

 only that it is not allowed to get wet. The explanation of this re- 

 markable action of the sublimate may be found in the extremely 



