harmless Hydrous piceus, the lively Notanecta, Gyrinus, and Nepa, are essential to the collection.
Among the larva, those of the Caddis fly should be kept in abundance, on account of the amusement afforded by their strange habits and their remarkable metamorphosis. Larva of the Dytiscus, known as the Water Tiger, of the Dragon fly, the gnat, the May fly, and of the two-winged fly, Stratiomys Chamcæleon, the pretty blood-worm, which is the larva of the Chironomus plumosus, a very pretty gnat, with feathered antennæ; and the telescope-tailed grubs of Helophilus pendulus, which, in its larva form, is one of the most curious examples in the cabinet, and, in its imago, is frequently mistaken for the honey-bee.
The drag-net will also bring out many curious water-mites, than which there can be no more interesting subjects for the microscope, or prettier objects for ordinary observation. While writing this, I have before me several specimens of the beautiful mites, Hydrachna geographica and abstergens (Müller), in a jar of Nitella; they are ever in action, treading the water as if it were air, with a kind of motion that cannot be termed swimming, but rather a walking or dancing, maintained with the greatest ease at any level, or at the bottom of the vessel. Another, and much more showy one, is the bright carmine-coloured mite Limnochares holosericea (Latreille), of which I find an abundance in a neighbouring brook. Its pretty, spidery motions, and vivid colouring, render a jar, containing a dozen specimens, very attractive to the eye of a student of nature.
