Ground or Blue Aphis, is a close relative of the proceeding, but it gets its living from the roots down in the soil, while the Green Aphis feeds in the air on the leaves. The Blue Aphis attacks a great many varieties of plants, particularly in hot, dry weather, and whenever Asters, Verbenas, Petunias, Centaureas, or such plants begin to droop, it will be found on examination, in three cases out of four, that the farthest extremities of their roots are completely surrounded by the Blue Aphis. The only remedy we have ever found for this pest is a strong decoction of tobacco, made so strong as to resemble strong coffee in color. The earth around the plants must be soaked with this so that the lowest roots will be reached. The tobacco water will not hurt the plants, but will be fatal to the insect, and if it has not already damaged the roots to too great an extent, may prove a remedy.