the boat-fly; a genus of insects belonging to the order of hemiptera. It generally inhabits the water, and always swims on its back, and is very swift in its motions. Its belly, which it shows while in the water, is of a yellowish white; its legs are long; when taken out of the water, it hops. It is indeed a very beautiful and very nimble little creature; and is common in the ponds of water in Hyde park, and in several other places about London. It has four wings, five legs, and no antennae; it is eight inches long, three broad, and two and a half thick. The body is black, and of a very particular form, being flattened at the belly, and rising to a ridge on the middle of the back; so that when it swims, which is almost always on the back, its body resembles a boat in figure.

The belly is jointed, striated, and hairy; and has a large opening at the tail, out of which, when hurt, it thrusts forth something resembling a sting. The head and shoulders are large, hard, and yellow, without any spots; the eyes are large and red, and of a somewhat triangular form. The nose is a long, green, hollow proboscis, terminating in a hard and sharp brown point; this, in its natural posture, is kept under the belly, and reaches to the middle pair of legs. The outer pair of wings are of a pale flesh-colour, with spots of a dead white; these are long, narrow, and somewhat transparent: they terminate in a roundish point, and perfectly cover the whole body. The triangular piece which stands between the top of the wings is hard, and perfectly black; the inner wings are broader and shorter than the outer ones; they are thin and perfectly transparent, and are of a pale pearl colour. The legs are green and hairy; the foremost pair are shortest; the middle ones longer than these; but the hinder pair are greatly longer than all the rest, so that they serve as oars, and are tufted with hair at the end to that purpose. This creature mostly lives in the water, where it preys on small insects, killing them and sucking their juices with its proboscis, in the manner of the water-scorpion and many other aquatic insects; and it seizes its prey violently, and darts with incredible swiftness to a considerable distance after it.

Though it generally lives in the water, it sometimes, however, crawls out in good weather; and drying its wings by expanding them in the sun, takes flight, and becomes an inhabitant of the air, not to be known for the same creature, unless to those who had accurately observed it before; when tired of flying, or in danger of an enemy, it immediately plunges into the water. If taken into the hand, it flings, and gives