PRESERVING SPIDERS, etc.. — Spiders, which from their rarity or the beauty of their markings it may be desirable to preserve, require the contents of the abdomen to be pressed out, or their bodies to be cut underneath. A first-rate article on preserving these crustaceans appeared in Science Gossip for January, 1868, in which the author points out what is just as well to bear in mind, which is "that the colouring matter or pigment is placed between the outer or abdominal covering and the pulpy contents within, upon a very delicate membrane, which adheres very loosely to both, but more firmly to the contents within; so that when the viscera or contents are rudely removed, and without much tearing, the whole mass will be found more or less coloured, while the outer skin will be left entirely transparent. To preserve, therefore, the beauty of spiders, this must be untouched."
He further says: "Make an incision along the ventral aspect of the abdomen, nearly its whole length, or as long as will enable the pulpy contents to be easily removed; then pinch up the pulpy mass with a small forceps, carefully avoiding any dragging; then, with sharp-pointed scissors, cut away the contents bit by bit until the whole is nearly removed, or until you can see the brilliant colour shining through what remains in the cavity — better leave a little too much than be too nice in clearing all away; then, with a blowpipe, distend the empty abdomen; it will very soon become firm, and retain its original form, but until it is so the blowing must be frequently repeated."
A correspondent to Science Gossip, page 21, 1868, says: "I found the best way to preserve spiders was to suspend them by a loop round their waist in a solution of glycerine 2/3, water 1/3. The solution may want changing once or twice at first, after that it will keep unchanged for years."
Fig. 36 — Blow-pipe for inflating larvae
PRESERVING CATERPILLARS. — The larvae of moths and butterflies may be preserved by pressing out the contents of their bodies, and by working from the head to the tail in a gentle manner, and assisting the removal of the mass by a careful dragging with a crochet needle. When empty, a little corrosive sublimate solution may be injected with a metal or glass blow-pipe, and the empty skin then distended by blowing into it through a very fine blowpipe, made by drawing out in a clear flame a small glass tube until it is attenuated to a fine point. This being inserted in the orifice at the last segment of the caterpillar, is kept in place by being tied round with a piece of darning cotton, or, better still, by a contrivance shown in Fig. 36 (the invention of Mr. Auld, in Science Gossip for 1872). A A are pieces of watch spring tied on the thick part of the blowpipe, and holding the caterpillar by pressure on the last segments when the point B is inserted.
Mr. Auld, I see by his article, used a spirit lamp under a glass jar to form a drying chamber while blowing; but I have myself found a "box iron" a most convenient arrangement. The inner iron, being heated in the fire, is placed in the chamber or "box," which it thoroughly heats; then removed, and the larvae introduced and blown out in the hot air, but not so full as to unnaturally distend the segments.
A certain loss of colour inevitably takes place in preserved larvae, which in the larger ones may be restored by colouring inside them with powder colours mixed in turps. Coloured wax is sometimes injected, and makes the skin very firm, but it is a delicate operation, requiring great skill in application. When finished, they may be "mounted" on green silk-covered wire, or, more naturally, on nicely modelled leaves of their various food-plants, by gum attached to their claspers.
It is often necessary to plunge the more delicate larvae into a weak solution of carbolic acid, or alum and water, to harden them before preservation.
SKELETONS OF ANIMALS. — Many people being under the impression that it is only necessary to remove the flesh of any mammal or bird in order to get a perfect skeleton, it may be as well to point out that as the flesh rots, so do the ligaments which hold the bones, and consequently the skeleton falls to pieces. When, therefore, you have made your skeleton by the means recommended by various authors, such as exposing it in an ant-hill, a wasp's nest, or to the attacks of the "blow-flies" or "mealworm" (the larvae of a beetle), to "tadpoles," or — as is the usual way with the bone preservers — by maceration in water for a lengthened period (after removal of a great deal of the flesh, the skin, and entrails), you will, after the careful removal of the flesh still remaining, and subsequent drying of the bones in the sun and air, find that nearly every bone will have to be attached to its fellow by fine brass wire, and in the case of the bones of large animals, each bone will have to be neatly drilled and coupled with brass wire of greater strength.