To kill, pinch them under the wings between the finger and thumb, or, for a collection, procure a "killing hottle," which may be bought from most naturalists, or nay be home-made. Get a wide-mouthed bottle, provided with a good cork or glass stopper, and into this put an ounce (for a 4-oz. bottle) of cyanide of potassium in lumps. Then mix up some plastei'-of-Paris, and pour this upon the cyanide, so as to cover it completely. Give the bottle a shake as the plaster is setting, so that it forms an even surface, and, when quite set, cover the plaster with a piece of blotting-paper to absorb the moisture and to keep the insect from contact withthedamp plaster. This blotting-paper should be renewed when necessary. The cyanide is a deadly poison, so must be used with care, and the bottle kept corked. Put the insect into the bottle, cork it up, and leave the insect in for about ten or fifteen minutes. A few drops of strong spirit of ammonia poured on a piece of cotton-wool in a bottle will also form a killing bottle. Bruised laurel leaves may also be put into a bottle, and prussic acid will be given off, thus forming another killing bottle. A few drops of chloroform poured upon blotting-paper at the bottom of a bottle will also stupefy the insects to death.

Nothing is required to preserve butterflies.