It would appear that insects injurious to vegetation are every year increasing in numbers, and this, with a greatly increased attention given to cultivation of late, has awakened, on the subject of entomology, a very general and active spirit of inquiry. On all sides people are seeking information concerning the names and habits of insects; they find, by dearly bought experience, that without some such knowledge it is almost impossible to contend successfully with the swarms of greedy bugs, beetles, caterpillars, and other pests that prey upon their crops. A large portion of the Eastern States have been severely scourged the present season with the "Palmer worm" so called. It has also been destructive in some parts of New York. The Rose dug has made its appearance in localities where it was never seen before. Species of Curculios, hitherto rarely seen, have been destructive in some places. The Apple borer, too, has, we are advised, found its way into new regions. These, and similar facts, are sufficient to call attention in earnest to the study of insect life and habits, and to give importance to works touching upon this subject. This treatise of Prof. Harris is the only one we have in this country of general practical utility.

The first edition was issued some ten years ago. "It formed one of the scientific reports which were prepared and published by the Commissioners on the Zoological and Statistical survey of Massachusetts agreeably to an order of the General Court, and at the expense of the State," The present edition is much enlarged and improved; a great amount of information and experience has been collected and embodied in it, adding greatly to its value. It contains a full account of the Psylla pyri, an important insect that has infested pear trees in some localities, some account of which was given in the February number of the Horticulturist, The Chinch bug, a destructive pest of grain crops in some localities; the Angoumois moth, or flying weevil; the Eurytoma Hordei, or joint worm; the Hessian fly, and Wheat fly, all notorious depredators on field crops have been fully and minutely treated of. There is also an account of the Cotton worm of the South, and of insects falsely charged with the potato blight. All the latest experience in regard to insects injurious to fruits and flowers, have been carefully collected and furnish information of the greatest value to every cultivator.

The work has but one defect, and that is, the want of illustrative drawings that would enable persons unlearned in entomology to identify insects. We trust that measures will be taken to supply this defect. The example of Massachusetts, in ordering the preparation of such a work as this, should be imitated by every State in the Union; in no other department of science could the necessary cost be better expended. The preparation of this treatise is not the only way in which Prof. Harris has conferred benefits on agricultural and horticultural pursuits; he is daily imparting information through the press and by pri? vate letters. We should wish to see him in a position, if it were agreeable to himself, where his entire attention might be devoted to this subject.