Haas a resemblance to a shrimp, and is of a most voracious disposition, devouring, isidiscriminalely, water-insects, tadpoles, newts, and even small fishes do not escape its ravages. When arrived at its full growth, it retires to the bank, and there forms a lkllow of at oval shape, where, in a few days, it changes to a chrysalis of a whitish hue, which, itt about three weeks, becomes a flying beetle.

The genus Hydropltilus, another aquatic race, bears a near resemblance to that Dytiscus. The principal European species,.

ilydrop/tilus piceus, is of a singular form; the thorax being extended beneath, into a very long, sharp-pointed spine, and the hind legs fringed with fine, bristly hairs, that enable them to resist the water and act like oars. The larva of this insect has puzIed many naturalists, by the unusual appearance of its legs; which, from the position of the head, unless cautiously examined, seem to be inserted in the back, instead of the under part of the body.

The female fly of this species diflBrs from all other coleopterous insects, in spinning a flat, circular web, o a silky substance, as a repo sitory for its eggs, which it leaves floating on. the water; whence, as soon as the larva are hatched, they commit then asclvcs to that dc

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