12 



that the cariyinfy on of the experiments forbade any examinations of 

 the roots in order to estimate the relative nmnber of aphides inhabit- 

 ing each series of plats. 



EXPEEIMENTS IN DKIVING THE ANTS PROM THE ROOTS OF CORN IN THE FIELD. 



During- June, 1886, a number of experiments were made to test the 

 immediate effect of fertilizers, including- salt, upon the aphides, and 

 also to learn if the ants could be induced thereb}^ to abandon or remove 

 their favorites to other plants. 



The substances used were two commercial fertilizers (Bunner bone 

 dust and bone guano), barnyard manure, and common salt. A double 

 experiment was made with each. The first two su1>stances were applied 

 (1) by scattering a tablespoonful on the surface of the ground about 

 the plant and sprinkling with water sufficient to wash it at once into 

 the soil, and (2) I)}" drawing the earth awa}" from the roots, scattering 

 the same amount of fertilizer about the roots, then replacing- the earth, 

 and sprinkling- the surface less thoroughly than with the first. The 

 barnj^ard manure was well-rotted and a quantity sufficient to till a pint 

 measure was used in the same way. The salt was used in the same 

 way as the manufactured fertilizers. 



The result, a week after, was that the "lice" were still about the 

 roots in every case, and, except where salt was used, the}^ were found 

 in the midst of the substances applied. The salt only drove them from 

 one portion of the roots to another. Sand dampened with kerosene 

 was then applied in the same wa}', but the surface application had no 

 effect, and that made directly to th(5 roots only drove the aphides from 

 one part of the roots to another, as did the salt. 



TREATING THE SEED BEFORE PLANTING. 



During the last two years Doctor Forbes, in Illinois, has been test- 

 ing a great number of substances with a view to treating the seed 

 with some repellent that would render it so obnoxious to the ants that 

 they would not place the aphides on the roots of the 3^oung plants. 

 It has indeed seemed possible to take advantage of the well-known 

 fastidiousness of these ants and iind something that, applied to the 

 seed, would not injure its vitality, but would give off an odor so dis- 

 agreeable to the ants that they would shun the vicinity of its applica- 

 tion. The writer tried something of this sort in 1887 — except that in 

 his experiments substances supposed to be offensive to the ants were 

 placed in the soil about the roots of the corn — but the results were 

 not satisfactory. In treating the seed, however, Doctor Forbes seems 

 to have had very encouraging success and he has permitted the writer 

 to use here the results of his experiments, which are quoted in brief 

 as follows: 



[Cir.8(i] 



