This puts the matter beyond doubt, if any before existed. I at once wrote to Mr. Tegetmeier to let him know that my experiments had, unknown to me, been anticipated, long ago, by Mr. Sowerby. Had he rescued his Planorbis shell, it would have compared very well with those forwarded to the _Field_ office in 1893. They had been exhibited at the Malacological Society, and no one was able to solve the mystery of their mutilation. This shows, to quote the _Field_[10] on the subject, ‘how easily statements that have been recorded may subsequently be overlooked and entirely forgotten.’ To return to our Beetle. The male is a handsome creature, from an inch to an inch and a quarter long, clad in olive-green, bordered with yellow, and exceedingly active. His mate is smaller, more soberly clad in brown, without the yellow markings, and the wing-cases are more or less furrowed. The first thing to notice is the shape of the body, oval and smooth, offering no resistance to the water. The hind pair of legs are flattened and fringed with hairs, so as to make capital paddles. In swimming the right and left legs are moved together. Now, though this Beetle lives in the water, it is made, so far as concerns its breathing apparatus, after the fashion of a Land Beetle, and consequently is compelled to come to the surface pretty frequently for a supply of air, which it obtains in this wise. Directly it ceases paddling it floats to the top of the water; and as the head is heavier than the tail the latter projects a little above the surface. Then the wing-cases are raised, and air flows in under them to the breathing holes on each side. The operation is not a long one, and as soon as it is over the Beetle is ready for another ramble round his dwelling-house. But if we do not supply our captive with food that he may take for himself, it is only right that we should feed him, which may be done at intervals--say, every other day. ‘Little, and often,’ is an excellent motto to guide us in our feeding; and though its adoption may entail some trouble, it will be more than compensated by the success that will attend our endeavours to keep the inmates of our aquarium in good condition. And the operation of feeding our Beetle will show us that he has some capital sense-organs, which are of as much, if not of more, use to him than his eyes.