I notice your Baldwinsville correspondent's inquiry regarding cocoons on the apple tree. I have frequently detected them in my orchard here, but had not detected the moth. So far as I can ascertain, they are, in common with at least two other apple tree insects which abound here, perfectly harmless. One of these is a minute black-winged fly, not unlike a very small wasp or female ant, which lays clusters of shining black eggs -two to three dozen together-under the loose bark. The eggs are exceedingly abundant, but the fly appears to be scarce. In its winged condition, it probably has another habitat, but I have detected it laying its eggs in the fall. These latter, under a good microscope, are very beautiful, being of the deepest black with the very highest polish. Does it exist with you? If it does, you cannot fail, when cleaning your trees in the spring, to have seen the eggs.

There is another insect, of whose harmlessness I am not so confident I believe it to be an aphis, but have never met with any description of it It is a clumsy, soft, bed-bug-looking crea- 1 ture, about the size of this familiar pest of a dark grevisn-green. regularly striated across the back. I find it only on the trunk and larger limbs of apple trees when the first warm weather commences, and it does not, so far as I have observed, remain longer than three or four week* It is gregarious, several hundred of them being herded close together, immoveable, apparently sucking the sap; but if disturbed, or frightened, they scatter instantly, some falling to the ground, others running with more speed than one would expect from their awkward appearance. I have not traced any direct injury to them, but as they are always full of sap, I presume they must weaken the tree. I kill them by taking a piece of cloth and covering the whole herd suddenly and crushing them. Can you give me name and particulars regarding them!

I read with much interest the article of your amusing and quaint correspondent, "Pisistratus." He is an amateur after my own heart-one of that class of men who dignify the mercantile profession, and having made money make good use of it, and make themselves and others happy by experimenting and ornamenting in a style which wo less fortunate mortals can rarely afford. But he is a good example of the difficulty of writing clearly and understanding^ on agricultural and horticultural topics. He complains of books "not imparting the whole knowledge required," and immediately falls into the same error-if error it can be called, when it is general with every one who is master of an art, when he attempts to teach it to those who know nothing of it He forgets that what is perfectly familiar to him is " Dutch " to the others. And thus as regards his rhubarb--I should like to try his plan if I knew how. Can you induce him to favor us with a detailed account! When are the roots taken up! What are they planted in in the barrel-in earth, or only in fresh manure! Does he water them! Is the manure put into the barrel from the plant to the top, or only over the barrel, leaving a vacancy between the plant and manure! Was manure used in the house!-or, if not, what was used to force! Will he be so good as to explain, step by step! F. -Gro$ie Isle, Mich.