Page:The Book of the Aquarium and Water Cabinet.djvu/150

138 anterior one is punctured, and runs parallel with the margin. The elytra are turned in at the sides, and the surface of each is marked with eleven striæ or longitudinal lines, composed of minute punctures. The terminal segment of the abdomen, together with the legs, are of a rust-red.

If we inquire by what means it is enabled to perform its elegant performances on the water, and which very closely resemble those of a skilful skater on the ice, we find that its structure is eminently fitted for such peculiar movements. In the first place, the antennæ are short and thick; if they protruded forward to a great length, as in Longicornes, they would seriously impede the freedom of action, which is the life and joy of this nimble fellow. They are clavate, and consist of seven closely-jointed rings, each antenna being attached by a slender peduncle to the upper and internal edge of a large radical joint furnished with an auricle at its outer side, which, like the lid of a box, shuts in the antennæ when unemployed, and protects