CHAPTER XLIII.

PREPARATION, CARE, AND DISPLAY OF INSECTS.

[Ill.u.s.tration: FIG. 94.--Manner of Folding Paper Envelope. A-B, First fold; B-C, second fold; A-D, third fold; B-F, fourth fold; A-E, fifth fold.]

[Ill.u.s.tration: FIG. 95.--b.u.t.terfly in Envelope.]

The next step after the capture of the specimens is to prepare them either for transportation or for the cabinet. If collecting upon a journey, or where facilities for the preparation of specimens for the cabinet are lacking, the insects may be preserved in papers. Common druggists'

envelopes are a very convenient resource for the preservation of lepidoptera. They may be purchased by the thousand at about sixty-five cents. If these cannot be had, envelopes may easily be made from pieces of paper, preferably stiff newspaper or common writing-paper upon which ink has not been used. The manner of folding these is ill.u.s.trated by Figures 94 and 95. Care should be taken to write upon the envelope, before the insect is placed in it, the date and the locality of capture. Beetles, if black and devoid of hairy vest.i.ture, may be preserved in alcohol, and the same course may be taken with many insects of other orders. It is preferable, however, to pack beetles and other hard-bodied insects in layers of cotton batting. A small box may be made to contain an immense number of insects in envelopes or in cotton, and they may thus be safely transported anywhere.

In case alcohol is used as a preservative all the specimens of a species should be sorted out and tied together in a small sack made out of thin netting, and to this should be attached a label giving the date and place of capture and a reference to the note-book. In case cotton layers are employed all the specimens of a species, if numerous, should be placed in one layer, and a memorandum to the same purport as the label inserted.

Insects are prepared for the cabinet by being mounted upon pins and "expanded." There are various sorts and sizes of insect-pins, but those made by Klaeger, of Berlin, are generally preferred at the present time by the leading entomologists of the world. The French pins and the so-called "Carlsbader pins" are too long and the points are too fine, and, therefore, too likely to be injured to make them desirable. The English pins are too short, and except in the case of very small insects, are not used by the best collectors. Insects should be mounted high upon the pin, _i.e._, in such a way that not more than one-fifth or at the most one-fourth of the pin shall be exposed above the body of the specimen. Dr. Staudinger, the celebrated lepidopterist of Germany, makes it his rule to mount all his specimens in such a way that the wings are elevated upon a plane one inch above the tip of the pin. The writer has had the greater part of his collection, of over fifty thousand specimens of lepidoptera, mounted at an average height of seven-eighths of an inch above the points of the pins.

The "English method" of mounting low down, and only leaving enough of the pin exposed below to permit of fixing the specimens in the cork at the bottoms of the drawers of the cabinet, is rapidly pa.s.sing out of vogue, even in England, and is giving place to the "Continental Method." Insect pins are of various sizes; adapted to the size of the insect which they are to carry. The most serviceable sizes and which will be proportioned to the majority of the insects which the collector is likely to take, are Klaeger's No. 3 and No. 5. For very large insects higher numbers may be employed, and for smaller insects lower numbers, though in the case of the latter it is perhaps better to use the short English pins and then to mount the specimens upon the bits of cork or pith which are themselves mounted upon the longer German pins. Such mounts are known as "double mounts" (see Fig. 96). The writer desires to utter a caution against the use of the common black insect-pins so often sold by dealers, and the sole stock in trade of one or two firms of opticians in this country. They are very liable to rust at the point and to bend, and are totally unsuited for use in humid, tropical, and semi-tropical climates, or for collections which are to be transported far over the seas. Beetles should always be pinned through the right elytron. Bugs should be pinned through the scutellum, as the small triangular piece between the elytra is called. All other insects should be pinned in the middle of the thorax, and care should always be taken to set the pins perpendicularly.

[Ill.u.s.tration: FIG. 96.--Double Mount. C, Long pin; P, pith; S, specimen mounted on short pin; L, label.]

[Ill.u.s.tration: FIG. 97.--Frame for Mounting Beetles. a, a, Wooden frame; A, B, paper drumhead.]

Having pinned the specimen the next step is to expand it properly. In the case of beetles this is done by simply arranging the feet and the antennae in such a way that they can easily be inspected. In doing this it is well to have a frame seven-eighths of an inch deep, or thereabouts, backed by a thin piece of soft pine, and covered on top by a sheet of paper, which has been first moistened and then pasted around the edges, and which when dry expands like a drumhead. (Fig. 97.) Upon this a number of beetles may be pinned, their feet drawn out, and there be left to dry. In the case of lepidopterous insects, and other insects having considerable expanse of wing, setting-boards are required. These are boards provided with a groove in the middle capable of receiving the body of the insect, and permitting of the expansion of their wings laterally. These boards should be of various widths, so as to be adapted to insects having various expanse of wings, and the grooves also should be of various depths, adapted to insects having bodies of various size. The best form of a setting-board, with which the writer is acquainted, is that given in Fig. 98. The narrow slit below the groove, which is intended for the reception of the body of the insect, admits of pa.s.sing the pin down to a proper depth, and the depth is regulated of course by the piece at the bottom of the setting-board. The two side pieces should always be from seven-eighths of an inch to an inch thick. The best material is soft, clean pine, or, better still, the wood of the Kiri-no-Ki (_Paulownia regalis_).

[Ill.u.s.tration: FIG. 98.--Setting-Board.]

[Ill.u.s.tration: FIG. 99.--Setting-Board. (After Riley.)]

[Ill.u.s.tration: FIG. 100.--Setting-Block. A, Groove for body of insect; B, nick for holding thread; C, cork to receive point of pin pa.s.sing through holes in bottom of A.]

[Ill.u.s.tration: FIG. 101.--b.u.t.terfly Expanded upon Setting-Block.]

Instead of setting-boards, setting-blocks (see Figs. 100 and 101), may be advantageously employed in setting smaller specimens, especially of the Hesperidae and the Noctuidae, the wings of which are refractory, and refuse to be treated in the method that has just been described. Instead of using strips of tracing muslin it is necessary, in the case of setting-blocks, to use threads or cords, which may be adjusted, as is shown in the figure.

Care should, however, be taken not to draw the thread or cord so tightly about the wings of the specimens as to cut into their vest.i.ture and thus leave marks.

[Ill.u.s.tration: FIG. 102.--Setting-Needle.]

The insects having been adjusted upon the board, care being taken that the pin is set perpendicularly, the next step is to draw out the wings in the position which they are to maintain when the specimen is thoroughly dry.

This is accomplished by means of what are known as "setting-needles" (see Fig. 102). They can easily be made by inserting ordinary needles into handles, which may be made of some soft wood. The writer generally employs as handles for his setting-needles matches, from which the sulphur tip has been removed. In drawing the wings into position care should be taken to plant the setting-needle immediately behind the strong nervure of the costal margin of the wing. Otherwise the wings are likely to be torn and disfigured. The rule in setting lepidoptera is to draw the anterior wings forward in such a way that their posterior margins form a right angle with the axis of the body, which rests in the groove in the middle of the setting-board. The posterior wings are then drawn forward in such a way as fully to expose their outline. The next step is to firmly fix the wings in position, as they have been placed. Some writers recommend for this purpose using short strips of paper over the wings, others recommend placing upon the wings pieces of gla.s.s, of a size sufficient to cover the entire wing. A far better plan is to employ strips of tracing muslin, such as is used by draughtsmen and engineers. These strips may be secured at the ends of the setting-board by thumb-tacks, and may be drawn down over the wings of the specimen and securely held by pins in place. Care should be always taken to nicely turn up the edge of the strips nearest to the body, so that a crease or depression may not be left upon the scales covering the wings of the insects when the specimen has been thoroughly dried. The wings having been arranged, the antennae and the feet may be brought forward and displayed in a natural position. Care should be always taken to lower the antennae so that they do not stand erect above the head. In the latter position they are very apt to become broken. A number of such boards may be conveniently arranged in a box, as shown in Fig. 103, and if strips of muslin are used, and are firmly held in place by pins, such a box may be transported from place to place, upon the backs of men or beasts, and the process of drying the insects may go on _en route_, while the naturalist is conducting his investigations. In this manner the writer carried four or five large boxes with him through the interior of j.a.pan (Plate XXIII., Fig. 2), and succeeded in bringing home with him nearly six thousand specimens, dried and ready to place in the cabinet. The length of time which is required for drying, varies of course a little with the temperature, and the amount of humidity in the atmosphere. In some climates it is almost impossible to absolutely dry the specimens, in others they dry very quickly. In the United States a week or ten days will generally suffice to secure that rigidity which is necessary in a cabinet specimen.

[Ill.u.s.tration: FIG. 103.--Box for Receiving Setting-Boards. _a_, Board partly withdrawn; _b_, =T=-shaped strip to hold board in place; _c_, sliding door of box; _d_, tongue on edge of door working in groove at front of sides.]

The process of drying may be hastened advantageously by placing the setting-boards in a cool oven. The temperature, however, should not be above 130 F. Some insects lose their color when dried, and it is impossible in certain cases to retain them. In some cases also the bodies of insects shrivel up very greatly and become distorted. It is very often advisable in such cases to make an incision into the abdomen and withdraw the viscera and stuff the body with cotton. Spiders should always be treated in this way, and so also the larger Mantidae and Locustidae. When the insects have become thoroughly dry, and their wings are rigid, they may be removed from the setting-board, and are now ready for the cabinet. In case, however, it is desired to transport them, as is the case with specimens that have been collected upon a journey, they may be pinned in boxes lined with cork or pith, with their wings "shingled" as in Fig. 104, and they may, if firmly secured to the bottom of the boxes, be in this shape transported for long distances; but it is always necessary to pack the box in which they are contained in an outer box, separating the inner box from the outer case by at least two inches of straw, excelsior, or some other light and elastic substance, to save the specimens from being jarred in transport.

[Ill.u.s.tration: FIG. 104.--b.u.t.terflies Pinned with their Wings Shingled.]

Specimens that have been preserved in paper, as described on page 328, in order to fit them for the cabinet, should be relaxed and then expanded. In order to relax them, one of the best methods is to place the envelope which contains the specimen between layers of cloth that have been dampened in pure water, to which has been added a small quant.i.ty of carbolic acid, enough to prevent mould. Be careful not to add too much carbolic acid.

Another method is to lay the specimens at the bottom of a jar, half-filled with sand, which has been moistened and well carbolized. The jar should be tightly closed, so as to retain the moisture. Specimens that have been fastened with pins may be placed on pieces of board, and then set in a jar, prepared in the way that has been described. After exposure to the moist atmosphere of the jar, or to the moisture contained within the towelling, for a period varying from a few hours to a day, the specimens will be sufficiently relaxed to permit of them being treated as if they had been freshly taken, and mounted and expanded upon the setting-board as described on page 331. It is well to have the top of the jar, before the lid is placed upon it, covered with a layer of blotting-paper, or some other substance which will absorb the moisture which otherwise might drip from the lid upon the specimens below. This is a precaution which is especially necessary in the case of b.u.t.terflies which are of a bright blue or a pale green color, and which are much disfigured by water stains.

Mould is one of the great enemies of the collector, and strenuous efforts should be made to prevent its appearance in the cabinet or among the specimens. In order to do this, it is well to secure a thorough desiccation of the specimens, but where it is impossible to thoroughly dry them, moulding may be prevented to a greater or less extent by placing between the paper envelopes pieces of blotting-paper which have been saturated with carbolic acid and permitted to dry. The sides of the boxes containing the specimens may also be painted with carbolic acid. Naphthaline in crystals may be introduced among the envelopes, and this appears in many cases to serve as a partial preventive of mould. When a specimen has been attacked by mould, the mould may be largely removed by thorough drying in a cool oven and then dusting off the specimen with a soft camel's-hair pencil that has been rubbed in carbolic acid and dried.

Specimens sometimes become greasy, and it is then desirable, if possible, to remove the grease with which their bodies and wings are saturated. The only method which can be employed advantageously is that of washing out the grease by means of benzoline, or some of the allied volatile mineral oils.

By immersing a greasy specimen for a considerable time in gasoline, it is possible to remove the grease. The specimen having been thus exposed should be placed in a cool spot, free from dust, and all the gasoline should be allowed to evaporate. Care should be taken to conduct this process away from fire and lights, in order to prevent an explosion. The writer has found that the best method for removing grease is to allow the gasoline to fall drop by drop upon the thorax of the specimen. The specimen is therefore placed in a very large gla.s.s jar, say six inches in diameter, and is fixed at the bottom upon a piece of cork, tightly secured in place. The gasoline is placed above and is allowed to filter down from the bottle in which it is contained upon the specimen drop by drop. In this way the grease is gradually washed out, and will be found after a while at the bottom of the jar in the form of thick globules, the density of which causes them to sink to the bottom. In the case of some large bombycid moths the writer has washed out as much as a teaspoonful of animal fat from the body and wings of the specimen, in the manner that has been described.

The receptacles into which entomologists place their collections vary somewhat according to the taste and the length of the purse of the collector. Some large collections are contained in boxes, and most of the coleopterists of this country, so far as the writer knows, have adopted these as receptacles for their collections. The boxes should be about two inches deep in the clear, the bottom should be lined with the best quality of cork, about one-fourth of an inch in thickness, and the whole papered inside with white paper. The lid should be fastened upon the lower part of the box, either by a tongue and groove or by thin strips nailed around on the inside and projecting above the margin of the bottom portion at least half an inch. These boxes should also be hinged. The material should be well-seasoned. Double boxes with cork on the top and on the bottom are sometimes used, and these may be prepared with backs resembling books, and may be placed upon their ends upon shelves. They should not be laid one upon the other, as the insects pinned upon the upper side are liable sometimes, through jarring, to become detached, and falling out to cause a breakage among the specimens. The writer employs in his own collection drawers twenty-two inches long, eighteen inches wide, and two inches deep, covered with gla.s.s, the gla.s.s cover being attached to the bottom by a tongue and groove.

The specimens should be kept in the dark, as exposure to light bleaches them, sooner or later. Great pains should be taken to keep out dust, mould, and insect pests, such as Anthrenus and Dermestes. Naphthaline crystals destroy mites and they cannot exist where it is abundantly present.

Anthrenus and Dermestes may be kept out of collections by naphthaline, but when they have been once introduced they will remain and propagate in spite of the presence of the drug. In order to exterminate them various agents are employed. The best is perhaps chloroform, and next to this carbon bisulphide. In buying the latter drug, care should be taken to purchase the washed and purified article, which is not as malodorous as the common varieties which used formerly to be sold by druggists. It is, however, highly explosive when mixed in quant.i.ty with the air, and care should be taken not to use it in proximity to a light. It has the advantage of destroying at once the imago, the larva, and, perhaps, the eggs of museum-pests. The writer makes it a point annually, in the early summer, to place sufficient chloroform or carbon bichloride in his cabinet drawers to exterminate anything that may be living there, and thus secures comparative immunity from insect attacks.

Instructions as to the use of labels may be restricted to the simple advice to make them small enough to permit of their being placed upon the pins bearing the insects, and to have them written legibly. Of course every label should bear, if it is possible for the student to determine them, the generic and the specific names of the insects, and that of the author of the specific name, together with the date and locality of capture. In writing labels a small crow-quill pen is to be preferred.

A great many instruments of different sorts will suggest themselves to the collector in the process of his labors as being more or less useful, but none will prove more so than the forceps. It is impossible to do good work in the cabinet without a forceps, and those made by Blake, of Philadelphia, are the very best.

_Books to be Consulted by the Collector for further Information as to Methods of Manipulating Specimens._

Packard: Guide to the Study of Insects. 8vo. Henry Holt & Co., New York.

Scudder: b.u.t.terflies. 8vo. Henry Holt & Co., New York. Kirby and Spence: Introduction to Entomology. Various editions.

McCook: American Spiders. Strecker: American Moths and b.u.t.terflies.

A great deal of practical and valuable information is to be derived from the pages of the following journals:

The Canadian Entomologist.

The Bulletin of the Brooklyn Entomological Society. Psyche.

_Names of Dealers in Entomological Supplies who are to be Recommended_.

John Akhurst, 78 Ashland Place, Brooklyn, N.Y.; pins, etc.

John Burr, North Fifth Street, Camden, N.J.; boxes, cabinets, etc.

Armstrong, Brother & Co., Pittsburgh, Pa.; cork. The largest cork manufacturing firm in the United States. Will cut cork of any size which may be ordered, within practical limits.

Blake & Co., 55 North Seventh Street, Philadelphia; forceps.

PART VI.--GENERAL INFORMATION.