One insect, the _ægeria exitiosa_, has committed great ravages among the peach trees. The larva begins the work of destruction about the beginning of October, by entering the tree, probably through the tender bark under the surface of the soil; thence it proceeds downwards, within the tree, into the root, and then turns its course upwards towards the surface, where it arrives about the commencement of the succeeding July. They voraciously devour both the alburnum and the liber, the new wood and the inner bark. The insects deposit from one to three hundred eggs within the bark of the tree, according to its capacity to support their progeny. The United States are not free from the scourge of the locust. The males have under each wing a ribbed membrane as thin as a gossamer’s web, which, when inflated, constitutes their musical organ. The female has a sting or drill, the size of a pin, and near half an inch in length, of a hard and brittle substance, which lies on the under surface of the body; with this the insect drills a hole into the small limbs of trees, quite to the pith; there it deposits through this hollow sting or drill some dozen or two of small white eggs. The time required to drill the hole and deposit the egg is from two to five minutes. When undisturbed, they make some half dozen or more insertions of their drill in the same limb, perhaps an inch apart, and these punctures usually produce speedy death to the end of the limb. They sometimes swarm about the forests in countless multitudes, making ‘melancholy music,’ and causing no less melancholy desolation. GENERAL REMARKS ON ZOOLOGY. The zoology of the United States opens a wide and interesting field of observation: it is more peculiar and striking than either the mineralogy or botany. The following general view of the mammiferous animals inhabiting North America is given by Dr. Harman. The number of species now ascertained is one hundred and forty-six, in which we do not include man; of these twenty-eight are cetacea, and one hundred and eighteen are quadrupeds. Among the quadrupeds, Dr. Harman reckons eleven species, of which no living trace is found in any part of the world; which cannot of course be considered as forming a part of our present zoology. The number of living species of quadrupeds is therefore one hundred and seven. The comparative numbers of the several orders are stated as follows, omitting man: Carnivora 60 Glires 37 Edentata 6 Pachydermata 2 Ruminantia 13 Cetacea 28 We may here introduce from Dr. Harman a statement of the number of North American quadrupeds, which he conceives to be common both to the new and old world.