are produced from larvæ which inhabit the water, which can both crawl and swim, and which generally live in holes they make in the bottom. They change their coats several times before they become nymphæ. They quit their skin on the surface of the water, but even after they become flies, they have another transformation to undergo before they are perfect animals fitted for generation. They make use of their wings only to fly to some dry bank, or trunk of a tree, where they gradually disencumber themselves of the whole of the outward habiliment they brought from the water, including their wings. They become lighter, more beautiful in colour, and then begin their sports in the sunshine-appearing like what might be imagined of spirits freed from the weight of their terrestrial covering. This last transmutation has been observed and fully described by some celebrated naturalists, in the case of the May flies, and one or two other species, and it probably will be found a general circumstance attached to the class, and I have often observed what appeared to

me to be the cast-off skins of the small species of ephemera on the banks of rivers and floating in the water. The green ephemera, or May fly, lays her eggs sitting on the water, which instantly sink to the bottom: and most of the duns, or small slenderwinged flies, do the same. The grey or glossy-winged May fly, commonly called the grey drake, performs regular motions in the air above the water, rising and falling, and sitting, as it were, for a moment on the surface, and rising again, at which time she is said to deposit her eggs. To attempt to describe all the variety of ephemeræ, which sport on the surface of the water at different times of the day, throughout the year, would be quite an endless labour. Some of them appear to live only a few hours, and none of them, I believe, more than a few days. In spring and autumn a new variety of these flies sometimes appears every day, or even in different parts of the same day. Of the beetle, or colyoptera genus, there are many varieties fed on by fishes. These insects, which are distinguished, as you know, by