In mounting these objects for the microscope it is well to have the part of the insect from which the scales are usually taken as a separate slide, so that the natural arrangement of them may be seen. This is easily accomplished with the wings of butterflies, gnats, &c.; as they require no extraordinary care. In mounting the _scales_ they may be placed upon slides, by passing the wings over the surface, or by gently scraping the wing upon the slide, when they must be covered with the thin glass. Of course, the extreme tenuity of these objects does away with the necessity of any cell excepting that formed by the gold-size or other cement used to attach the cover. The scales of the podura should be placed upon the slide in a somewhat different manner. This insect is without wings, and is no longer than the common flea. It is often found amongst the sawdust in wine-cellars, continually leaping about by the aid of its tail, which is bent underneath its body. Dr. Carpenter says:--“Poduræ may be obtained by sprinkling a little oatmeal on a piece of black paper near their haunts; and after leaving it there for a few hours, removing it carefully to a large glazed basin, so that, when they leap from the paper (as they will when brought to the light), they may fall into the basin, and may thus separate themselves from the meal. The best way of obtaining their scales, is to confine several of them together beneath a wine glass inverted upon a piece of fine smooth paper; for the scales will become detached by their leaps against the glass, and will fall upon the paper.” These scales are removed to the slide, and mounted as those from the gnats, &c. When the podura has been caught without the aid of the meal, it may be placed upon the slide, under a test-tube, or by any other mode of confinement, and thus save the trouble of transfer from the paper before mentioned. Another method is to seize the insect by the leg with the forceps and drag it across the slide, when a sufficient quantity of scales will probably be left upon it. These scales are usually mounted “dry;” but Hogg recommends the use of Canada balsam (Chapter III.) as rendering their structure more definite when illuminated with Wenham’s parabolic reflector. Some advise other methods, which will be mentioned in Chapter IV. As most _insects_ when undissected are mounted in Canada balsam, the different modes of treatment which they require will be stated in another place.