Good things should always, when practicable, be set out at once, as the pubescence is apt to get matted if they are consigned for too long a period to the laurel or cyanide bottle; but such as remain unmounted can be put in a little muslin bag, and deposited in laurel until a more convenient opportunity. Beetles also, when taken in large numbers during an expedition into a productive locality, may be collected indiscriminately into a bottle containing sawdust (sifted to get rid both of large pieces and actual dust), slightly alcoholized, or with a small quantity of carbolic acid or cyanide of potassium in it. Each night, on reaching home, these will be found to be dead, and they can then be transferred to a larger bottle or air-tight tin can, partially filled with the same materials and a little carbolic acid to check undue moisture. Filled up with sawdust, this will travel in safety for any distance, and almost any time.
Species of moderate size, say up to that of an ordinary Harpalus, are in this country usually mounted on card. Much is to be said both for and against this practice: it enables the proportions and formation of limbs to be well appreciated, and it preserves the specimens securely; but there can be no doubt that it prevents an inspection of the under side, except at the slight trouble of extra manipulation in floating off in cold water and reversing, and that the gum used clogs the smaller portions of the insect that come in contact with it. Specimens larger than those mentioned should be pinned through the centre of the upper third of the right wing-case (never through the scutellum or thorax), and the limbs extended in position with pins on a setting board, made of a flat strip of cork glued on deal. Both these and the mounted examples must be left to dry, for a week at least, in the open air: if the boards are fitted in a frame, they can be reversed (as soon as the gum is dry in mounted specimens), so that the specimens are bottom upwards—dust cannot then collect on them, and there is less chance of mites attacking them. Specimens dry more rapidly in spring and summer than at any other time, and of course more readily in dry weather.
For mounting specimens, five or six small pieces of the finest and most transparent gum tragacanth, or "gum dragon," with rather less than the same number of pieces of clear gum arabic, are to be put in a wide-mouthed bottle with about a large wine-glassful of cold water. In a short time (twenty-four hours at most) the gum absorbs the fluid and swells; then add half as much more water, and stir the mixture, which, on being left for another twenty-four hours at most, will be ready for use. The mixture should be dull white, of even texture, and not quite fluid. Never make a large quantity at one time, or be persuaded to put anything else into it. Card for mounting should be the whitest, smoothest, and best that can be procured. "Four-sheet Bristol board" for large specimens, and three-sheet for ordinary use, are about the proper degrees of thickness. Robersons, of Long Acre, artists' colourmen, have promised the writer to turn out cardboard of this kind with an extra milling, to ensure a good surface. Upon strips of this card, pinned on a setting board, the insects to be set out are mounted, one at a time, and not too close to each other, each on a separate "dab" of the gum, the limbs being duly set out with a fine pin or needle mounted in a paint-brush stick. A pin with the point very finely turned, so as to form a minute hook, is very useful; and for extremely minute work a "bead-needle" is valuable. The gum-brush should not be used in setting, but one or two very fine-pointed camel's-hair brushes may be found of advantage. Before mounting, reverse the specimen on the blotting-paper, and brush out its limbs as far as practicable with a damp flat brush. Very refractory individuals may require to be gummed on their backs; as soon as the gum is dry, their limbs can be more easily got into position, and they can then be gently damped off their temporary mount, and treated as above.
A small pair of brass microscope-forceps, ground or cut to a minute point, will often materially assist in getting refractory limbs into position. French white liquid glue (not made of shell-lac) is useful for fastening down larger specimens, as it is very strong and dries readily; and with a very small quantity of it rows of specimens can quickly and securely be roughly mounted, in the Continental way, which is preferable in many cases to leaving the insects for a long time in laurel before setting them out. Such specimens can afterwards, if desired, be relaxed by leaving them on damp sand, or in the cyanide or laurel bottle, and be then set in the way above indicated.
Care must be taken, in setting, not to put the specimen lop-sided on the card, or to distort its segments unnaturally by pulling them out of position, &c., and not to allow gum to lodge anywhere on the upper surface. It is easy, soon after a specimen is securely mounted, to remove with clean water and brush any superfluous gum. In preparing such insects as are liable to "run up" in drying (e.g. the Staphylinidæ), the abdomen should be duly pulled out by a bead-needle inserted at its apex; and to prevent the contraction of the internal muscles in drying, this part may be held with the liquid glue above mentioned. Usually, by putting these insects as soon as mounted into a box and keeping it closed for a few hours, while the first drying takes place, the proper dimensions of the abdomen may be preserved, and thus the natural facies of the insect retained. The contents of the bodies of very large insects may well be removed, either by the anal orifice, or by an incision on the lower side of the abdomen. The Oil-beetles (Meloë) alone require careful stuffing. This is best done by separating the entire abdomen from the metathorax, beneath the elytra, and close to their point of insertion: the body is then easily emptied and washed out, and may be filled with cut-up wool, which packs closely; when gummed on again, the junction is not visible, and the entire insect preserves its wonderfully obese appearance.
To save time, in mounting many specimens, it is better to merely gum straight on the strip of card as many specimens as can be managed at a sitting. The left side of each of these can then be slightly damped with clear cold water, and its left limbs set out: when all are thus done, the first one will be nearly, if not quite, ready to have its right side treated in like manner; and so on to the end. Very refractory specimens will sometimes require to be even held down with little braces of card on pins, and to have each limb damped and set out by a separate operation. The card of large specimens will often curl upwards in drying, owing to the amount of damp: to counteract this, the lower face of the card may be washed with a wet brush, just before gumming its surface.
Before putting insects away, when dry, the individual specimens should be cut off the strips of card by a straight cut on each side, one at right angles to the sides in front, and another behind, all (except the last) close to the tips of the limbs as set out, so that the whole card forms a parallelogram. A very little practice will enable the operator to do this both certainly and quickly. No two individuals (save perhaps a male and female, of whose sexual relations there can be no doubt, or an example mounted on its back, to show its under side, along with a member of the same species) should be allowed to continue on one card; much less should a row be left together. The reason of this is, that in many cases species closely resembling each other often get confused; and it is, moreover, difficult to get a glass of anything but a very low power to bear upon all parts of the individuals without injuring some of them. Each specimen should have sufficient card left behind it to allow of a glass of high power being passed between it everywhere and its pin. The pin should perforate the card in the middle of, and close to, its hinder margin; and the whole card be lifted three-fourths up the pin, to keep it from mites and dirt as much as possible. Proper entomological pins can be obtained of all sizes at the agents of Edelsten, 17, Silver Street, St. Martin's-le-Grand; also (with all other apparatus) of any natural-history agent or dealer in London; such as Mr. E. W. Janson, 28, Museum Street, or Cooke, New Oxford Street. "No. 8" pin is, perhaps, the most useful size. In removing many specimens, proper insect forceps will be found handy: these can be obtained at the two last addresses; or of Buck, cutler, Tottenham Court Road.
Specimens will occasionally become discoloured with grease, usually from defective drying, though many water beetles and internal feeders, and most autumn-caught specimens, are specially liable to this defect. Benzine is an effectual remedy for it and for mites, and can be liberally applied with a brush. Carbolic or phænic acid, dissolved in that fluid (or alone, see p. 64), is an effectual safeguard against mould from damp; and when in solution with water, this acid has been found useful as a wash for card and boxes, which then are not attacked by mites. To re-card a specimen that has become discoloured (whether from either of these causes, or from age), it is only necessary that it should be floated in cold water for a few minutes; the insect can then be dried, well saturated with benzine, and again mounted, looking as fresh as ever. But, in re-carding specimens, it is necessary to be very careful with such as were originally kept too long in a laurel or cyanide bottle, as they are apt to become so rotten that a little damp will cause a "solution of continuity."
As to storing the specimens when quite dry, I can add nothing to the excellent observations of Dr. Knaggs, at p. 65; the same remarks applying with equal force to Coleoptera; except, perhaps, that, even when the collector has (and is satisfied with) a cabinet, he is likely, in proportion to the real work done by him, to establish type-boxes of all the difficult groups.