In order to prevent the ravages of insects, all specimens, before putting them away into the boxes or drawers of the cabinet in which they are to be preserved, should be placed in a tight box in which chloroform, or, better, carbon bisulphide, in a small pan is put, and they should be left here for at least twenty-four hours, until it is certain that all life is extinct. Then they should be transferred to the tight boxes or drawers in which they are to be kept. The presence of insect pests in a collection is generally first indicated by fine dust under the specimen, this dust being the excrement of the larva which is committing depredations upon the specimen. In case the presence of the larva is detected, a liberal dose of chloroform should at once be administered to the box or tray in which the specimen is contained. The specimen itself ought to be removed, and may be dipped into benzine. Naphthaline crystals or camphor is generally employed to keep out insect pests from boxes. They are very useful to deter the entrance of pests, but when they have once been introduced into a collection neither naphthaline nor camphor will kill them. Naphthaline is prepared in the form of cones attached to a pin, and these cones may be placed in one corner of the box. They are made by Blake & Co. of Philadelphia, and are in vogue among entomologists. However, a good substitute for the cones may very easily be made by taking the ordinary moth-balls which are sold everywhere. By heating a pin red-hot in the flame of an alcohol-lamp it may be thrust into the moth-ball; as it enters it melts the naphthaline, which immediately afterward cools and holds the pin securely fixed in the moth-ball. In attaching these pins to moth-balls, hold the pin securely in a forceps while heating it in the flame of the lamp, and thrust the red-hot pin into the center of the ball. Naphthaline crystals and camphor may be secured in the corner of the box by tying up a quantity of them in a small piece of netting and pinning the little bag thus made in the corner of the tray. By following these directions insect pests may be kept out of collections. It is proper to observe that while carbon bisulphide is more useful even than chloroform in killing pests, and is also cheaper, it should be used with great care, because when mixed with atmospheric air it is highly explosive, and its use should never take place where there are lamps burning or where there is fire. Besides, its odor is extremely unpleasant, unless it has been washed in mercury.
Greasy Specimens.—Specimens occasionally become greasy. When this happens they may be cleansed by pinning them down on a piece of cork secured to the bottom of a closed vessel, and gently filling it with benzine, refined gasoline, or ether. After leaving them long enough to remove all the grease they may be taken out of the bath and allowed to dry in a place where there is no dust. This operation should not take place near a lighted lamp or a fire.
Mould.—When specimens have become mouldy or mildewed it is best to burn them up if they can be spared. If not, after they have been thoroughly dried remove the mould with a sable or camel's-hair pencil which has been rubbed in carbolic acid (crystals liquefied by heat). Mildew in a cabinet is hard to eradicate, and heat, even to burning, is about the only cure, except the mild use of carbolic acid in the way suggested.
Repairing Specimens.—Torn and ragged specimens are to be preferred to none at all. "The half of a loaf is better than no bread." Until the torn specimen can be replaced by a better, it is always well to retain it in a collection. But it is sometimes possible to repair torn specimens in such a way as to make them more presentable. If an antenna, for instance, has been broken off, it may be replaced neatly, so that only a microscopic examination will disclose the fact that it was once away from the place where it belonged. If a wing has been slit, the rent may be mended so neatly that only a very careful observer can detect the fact. If a piece has been torn out of a wing, it may be replaced by the corresponding portion of the wing of another specimen of the same sex of the same species in such a way as almost to defy detection. The prime requisites for this work are patience, a steady hand, a good eye, a great deal of "gumption," a few setting-needles, a jeweler's forceps, and a little shellac dissolved in alcohol. The shellac used in replacing a missing antenna should be of a thickish consistency; in repairing wings it should be well thinned down with alcohol. In handling broken antennæ it is best to use a fine sable pencil, which may be moistened very lightly by applying it to the tip of the tongue. With this it is possible to pick up a loose antenna and place it wherever it is desired. Apply the shellac to the torn edges of a broken wing with great delicacy of touch and in very small quantity. Avoid putting on the adhesive material in "gobs and slathers." Repairing is a fine art, which is only learned after some patient experimentation, and is only to be practised when absolutely necessary. The habit of some dealers of patching up broken specimens with parts taken from other species is highly to be reprobated. Such specimens are more or less caricatures of the real thing, and no truly scientific man will admit such scarecrows into his collection, except under dire compulsion.
[a]Fig. 73.]—Butterflies pinned into a box overlapping one another, or "shingled."
Packing and Forwarding Specimens.—It often becomes necessary to forward specimens from one place to another. If it is intended to ship specimens which have been mounted upon pins they should be securely pinned in a box lined with cork. A great many expanded specimens may be pinned in a box by resorting to the method known as "shingling," which is illustrated in Fig. 73. By causing the wings of specimens to overlap, as is shown in the figure, a great many can be accommodated in a small space. When the specimens have been packed the box should be securely closed, its edges shut with paper, after some drops of chloroform have been poured into the box, and then this box should be placed in an outer box containing excelsior, hay, cotton, or loose shavings in sufficient abundance to prevent the jarring of the inner box and consequent breakage. Where specimens are forwarded in envelopes, having been collected in the field, and are not pinned, the precaution of surrounding them with packing such as has been described is not necessary, but the box in which they are shipped should always be strong enough to resist breakage. Things forwarded by mail or by express always receive rough treatment, and the writer has lost many fine specimens which have been forwarded to him because the shipper was careless in packing.
Pins.—In the preceding pages frequent reference has been made to insect-pins. These are pins which are made longer and thinner than is the case with ordinary pins, and are therefore adaptable to the special use to which they are put. There are a number of makers whose pins have come into vogue. What are known as Karlsbader and Kläger pins, made in Germany, are the most widely used. They are made of ordinary pin-metal in various sizes. The Karlsbader pins have very fine points, but, owing to the fineness of the points and the softness of the metal, they are very apt to buckle, or turn up at the points. The Kläger pins are not exposed to the same objection, as the points are not quite so fine. The best pins, however, which are now made are those which have recently been introduced by Messrs. Kirby, Beard, & Co. of England. They are made of soft steel, lacquered, possessing very great strength and considerable flexibility. The finest-sized pin of this make has as much strength as the largest pin of the other makes that have been mentioned, and the writer has never known them to buckle at the tip, even when pinned through the hardest insect tissues. While these pins are a little more expensive than others, the writer does not fail to give them an unqualified preference.
[a]Fig. 74.—Butterfly-forceps, half-size.]