This able entomologist has sent the following letter to the Boston Cultivator, as a guide to cultivators. As the recommendation of one who has studied the habits of this insect very thoroughly, it is worthy of attention.

Mr. Editor: - These depredators have begun their summer work in good earnest. On the 27th, I saw cherries not bigger than small peas, and plums still smaller, that had been stung; and the next day, shaking brought down the weevil from a plum tree. From the appearance of the fruit, the weevils must have been busy a week or more ago. Those persons who wish to save their plums and cherries, should immediately begin to use such means as may prove best for protecting the fruit.

Showering the trees with lime-water, or throwing the fluid upon them with a syringe, till it forms a white coat on the young fruit, is said to be an effectual preservative from the at-tacks of the plum-weevil. It may be asked, however, whether we shall not have to shower our cherry trees and our apple trees, also. It is a well established fact, that the plum-weevil attacks all the following fruits, namely: plums, cherries, apples, nectarines, apricots, and peaches and even walnuts. The- whitewash may protect the plums, but the other fruits will be only the more sure to suffer, unless protected in like manner; and, when it comes to showering big trees and whole orchards in order to save the fruit, we shall begin to make unfavorable estimates of the cost and of the time required.

Sprinkling salt upon the surface of the ground has been repeatedly recommended, and some cultivators have applied it abundantly to the soil around plum trees; but it seems with very doubtful results. Some of us have lately had an opportunity of testing the efficacy of sea salt on a large scale, where our gardens (as was the case with mine) have been thrice overflown by the sea, during the high tides of last April. We shall soon find out whether the brine will have any effect upon the weevils, or will do our trees good in any other way. It is not yet time to make up an opinion thereon.

Of other remedies I can speak with much ployed in laying their eggs, or stinging the fruit, as this process is commonly called. Let a large sheet, divided halfway through the middle, be spread under the the trees, every morning early, and every evening after sunset; then, if the tree be suddenly jarred by a few smart blows, the weevils will drop upon the sheet as if dead, looking in their motionless state, like little blackish buds. Gather them up immediately, and throw them into a tin pail having a little water therein, and when the gathering is finish-cd, put them into the fire. Most of the insects thus caught napping, will be found to be females; and, as each female lays a large number of eggs, it is apparent that in this way, we shall nip the future brood in the bud. Plum trees, peach trees, and cherry trees, when not too large, and small apple trees, may thus be protected to some extent. But, as the weevils fly well, especially in the middle of the day, we may expect to be visited by some from the gardens and orchards of our neighbors, and even from others distant half a mile or more.

The remedy, to be effectual therefore, requires to be universally adopted.

Let swine be suffered to go at large and to root in the old orchards, and they will do their part in killing and eating the weevils while in a chrysalis state in the ground. Gather up all wind-fallen, immature and wormy fruit, daily. or twice a day, put it into barrels or tubs, and pour boiling water over it. Let this be done faithfully by every owner of a fruit tree, and my word for it, there will soon be a sensible diminution of the number of the insects; and a much greater amount of sound fruit will be pro-duced. This simple remedy can be employed by almost every one, at a comparatively trifling expense. It is because it has been so much neglected, that we now have so much wormy fruit; and the evil is evidently very much on the increase.

There are, in fine, but two resources that come within our power; either to make a general business of killing destructive insects in their season, by direct attacks upon them in their various forms; or, to starve them to death, by cutting down all our fruit trees. T. W. Harris. Cambridge, Mass., May 80, 1851.

Answers to Correspondents.