The female of this beetle deposits a single egg in an oblong slit, about one eighth of an inch long, which it has previously formed with its beak in the stalk of the potato. The larva subsequently hatches out, and bores into the heart of the stalk, always proceeding downward toward the root. When full grown, it is a little more than one fourth of an inch in length, and is a soft, whitish, legless grub, with a scaly head. Hence it can always be readily distinguished from the larva of the stalk-borer, which has invariably sixteen legs, no matter how small it may be. Unlike this last insect, it becomes a pupa in the interior of the potato-stalk which it inhabits: and it comes out in the beetle state about the last of August or beginning of September. The stalk inhabited by the larva wilts and dies. The perfect beetle, like many other snout-beetles, must of course live through the winter, to reproduce its species the following spring. In Southern Pennsylvania, some years, nearly every stalk of extensive fields is infested by this insect, causing the premature decay of the vines, and giving them the appearance of having been scalded. In some districts of Illinois, the potato crop has, in some seasons, been utterly ruined by this snout-beetle, many vines having a dozen larvae in them. This insect attacks no plant but the potato. ~The Potato-Worm~, (_Sphinx 5-maculata_, Haworth.)--This well-known insect, the larva of which (Fig. 3,) is usually called the potato-worm, is more common on the closely allied tomato, the leaves of which it often clears off very completely in particular spots in a single night. When full-fed, which is usually about the last of August, the potato-worm burrows under the ground, and shortly afterward transforms into the pupa state, (Fig. 5.) The pupa is often dug up in the spring from the ground where tomatoes or potatoes were grown in the preceding season, and most persons that meet with it suppose that the singular jug-handled appendage at one end of it is its _tail_. In reality, however, it is the _tongue-case_, and contains the long, pliable tongue which the future moth will employ in lapping the nectar of flowers. The moth itself (Fig. 4) was formerly confounded with the tobacco-worm moth, (_Sphinx Carolina_, Linnaeus,) which it very closely resembles, having the same series of orange-colored spots on each side of the abdomen. The gray and black markings, however, of the wings differ perceptibly in the two species; and in the tobacco-worm moth there is always a more or less faint white spat, or a dot, near the centre of the front wing, which is never met with in the other species. The potato-worm often feeds on the leaves of the tobacco plant in the Northern States. In the Southern States, in Mexico and the West-Indies, the true potato-worm is unknown, and it is the tobacco-worm that the tobacco-grower has to fight. The potato-worm, however, is never known to injure the potato crop to any serious extent.