Acarus the Plant Mite. Class Arachnids. The following are the chief of those known to t\he gardener. Acarus tellarius, the Red Spider, is one of the gardener's most troublesome foes. Its colour varies from yellowish to red-brown, and though almost invisible from its minuteness, yet it preys most destructively upon some trees and herbaceous plants in our hot-houses, us well as upon the kidney-bean, lime tree, etc, out of doors in dry summers. A. holosrrircus is another species, distinguishable to an unscienced eye chiefly by its scarlet colour. To destroy them in the hothouse, there is no plan so effectual as heating the flues or pipes, and sprinkling upon them sulphur. The air is thus gently impregnated with the vapour of sulphur, for it begins to evaporate at a heat of 170°. This vapour is fatal to the insect where the air is thoroughly impregnated with it, and the work of destruction is completed by syringing the infested plants with water. This last is the only practical remedy to plants in our borders, unless they can be covered over so that the fumes may be confined, whilst the sulphur is volatilized over a hot-water plate. Potted plants maybe submitted to the vapour of sulphur in a similar way. The vapour of spirit of turpentine is said to be as effectual as sulphur.

Acarus hortensis, the Garden Mite, thorax ochreous, abdomen white, has been found upon the roots of the cucumber, upon which it is said to prey. I believe it to be the same Acarus often so abundant upon the root of cabbages affected with the Ambury. A. geniculates is a minute, red, shining mite, gregarious, and congregating during spring in prodigious numbers upon the bark of the plum and other fruit trees, near the base of the twigs, and looking like a gummy exudation. By extracting the sap they doubtless weaken the tree, and reduce its productiveness. - Gard. Chron.