186 HOUSEHOLD INSECTS 



sugar 20 grams, water 100 cubic centimeters. The arsenic 

 is dissolved in a portion of the water by boiling and the 

 sugar in the remainder. The two portions are then mixed 

 and enough water added to make up for the loss by 

 evaporation in boiling. When the solution was placed 

 about in small dishes, as was described for the tartar 

 emetic, the ants, in some cases at least, gradually left the 

 vicinity. 



C. W. Woodworth obtained the best results in killing 

 the Argentine ant by the use of a very weak solution of 

 arsenic and sirup. He found that by reducing the arsenic 

 to between one-fourth and one-eighth of 1 per cent that 

 the ants would take large quantities of the poisoned mate- 

 rial to their nests and feed it to the young and the whole 

 nest would be killed by slow poisoning. The most con- 

 venient way to feed the poison was by placing a sponge 

 saturated with the solution in jars with perforated covers. 

 The ants will enter the jars, fill themselves with the sirup, 

 and carry it away. 



In a later experiment Nickels used sodium arsenite 

 which contains about 57f per cent of arsenic. To make a 

 weak solution, he dissolves a trifle over one ounce of the 

 arsenite in a little hot water. When dissolved it is added 

 to a sweetened solution of 20 pounds of sugar dissolved in 

 three quarts of water. It is necessary to heat the sirup 

 mixture to thoroughly dissolve the sugar. 



To make a small amount of the mixture, dissolve 3 

 grams of the arsenite in a little water and add it to a 

 sweetened sirup of 2 pounds of sugar dissolved in J of a 

 pint of water. He says, "We have established that it is 

 possible to exterminate the Argentine ant and to absolutely 

 prevent its spread." 



