Page:The Book of the Aquarium and Water Cabinet.djvu/145

Rh the dragon-fly, and do not go through their metamorphosis well without such food.

The imago is a handsome creature, with strong hooked claws, furnished with amber hairs, which, under a lens, resemble very closely the claws of a crab. The elytra are beautifully tinted with rich green and bronze, and the divisions of the head and thorax separated from the abdomen by sharp, whitish lines. Small fishes make the best diet for this beetle; but as this food fouls the water, it is best to keep them in clear jars, with a few pebbles and weeds, and once a week remove them to another vessel, to be fed. This plan preserves the brightness of the beetle jar, and prevents the annoyance of effluvia.

.—This is the largest of our native aquatic beetles, and, with the exception of the stag-beetle, it exceeds in bulk any other species of indigenous Coleoptera. It is common in the brooks and ponds in southern counties, but becomes rare as we travel northwards. In the larva state this is a rapacious and blood-thirsty insect, and of so destructive a character as to deserve its French name of ver-assassin. In that early condition it resembles a large soft worm, of a somewhat conical form, provided with six feet, and having its large scaly head armed with two formidable jaws. The head moves with such freedom in all directions, that it can readily seize small shell-fish and other mollusca floating on the surface, without altering the horizontal position of the body maintained in swimming; and it is even bent backwards, and devours its prey more conveniently by using the back as a kind of support. These larvæ swim