Part 5

The field box should be made of tin and should have a sheet of cork securely fastened at the bottom. In one corner of the box, tied in gauze and securely fixed in place, there should be a few lumps of cyanide. Into this box the specimens should be pinned as they are taken from the collecting jar, and the lid of this box should be kept tightly closed most of the time, being opened only when the transfer of the pinned specimens to the interior of the box is ready to be made. Inasmuch as pinning insects on the field is not always satisfactorily accomplished, the writer prefers not to pin them, but to carry with him a supply of small pay-roll envelopes, into which the insects are put, and these envelopes are then put into a box which has some cyanide secured in it, as has already been described. The writer also carries with him a little phial of chloroform in his vest pocket, and he sometimes uses this to stun insects or puts a few drops into the collecting box and then closes it. The objection to the use of chloroform is that it induces spasms of the thoracic muscles, and butterflies killed by the use of chloroform are not nearly so easily mounted as specimens which have been killed with cyanide. Beetles, wasps, and other hard-bodied insects should not be put into the same collecting jars as those which are used for butterflies, as they are very apt to injure the latter, tearing and spoiling the wings. If the collector is engaged in taking other insects besides butterflies and moths, he should have special jars in which to put the beetles and other hard-bodied and spiny things.

If the collector does not wish immediately to mount his specimens, but to preserve them for mounting at a future time, they may be left in the envelopes of which I have spoken, or may be “papered.” The simplest way of putting up butterflies in papers is to take an oblong piece of any kind of moderately good paper and fold it as indicated in the diagram (see Plate E, Fig. b), first folding on the line a-b, then on a-d and c-b; then on the lines b-f and e-a, as marked in the diagram. The result is the enclosure of the insect as shown in Plate E, Fig. c. A hundred or more of such envelopes may be put into an ordinary cigar box. Such boxes, filled with butterflies, in order to prevent mould and the ravages of pests, should have some chloroform or carbon bisulphide put into them and afterward a spoonful or two of naphthaline crystals. Then they should be closed and sealed up by pasting strips of paper over the edges. Butterflies thus collected on journeys may be safely carried for long distances without injury, or even transmitted through the mails provided the boxes are strong enough to resist crushing. When on journeys the writer of these paragraphs always papers his specimens, bringing them home to be later carefully mounted at his leisure. It is of the utmost importance to note on each envelope the place and the date of capture, so that these may later be placed upon the little labels or tickets which are put upon the pins after the insects have been expanded and mounted for display.

MOUNTING BUTTERFLIES

The writer cannot do better in dealing with this subject than to transfer from “The Butterfly Book” the substance of the directions there given in relation to this matter.

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When the collector has time enough at his disposal he should at once mount his specimens as they are intended to be displayed. The insect should first of all be pinned. For this purpose “insect pins” should be used. These are made either of soft steel or of pin metal. The first are to be preferred, except in very damp climates, where they sometimes rust if they have not been properly enamelled with shellac. The pin should be thrust perpendicularly through the thorax, midway between the wings, and at a considerable elevation upon the pin. It should then be placed upon the setting board or setting block. Setting boards or setting blocks are pieces of wood having a groove on the upper surface of sufficient depth to accommodate the body of the insect and to permit the wings to be brought to the level of the upper surface of the board (see Plate D, Figs. 6 and 7; and Plate E, Figs. d, e, f). They should also be provided either with a cleft or a hole which will permit the pin to be thrust down below the body of the insect for a considerable distance. As a rule the wings of all specimens should be mounted at a uniform elevation of about seven eighths of an inch above the point of the pin. This is known as the “continental method” of mounting, and is infinitely preferable to the old-fashioned “English method,” in which the insect was pinned low down upon the pin, so that its wings touched the surface of the box.

EXPLANATION OF PLATE E

Fig. a. Vivarium, or cage in which to breed caterpillars.

a, base, kept even by cleats, g, g; on this is placed a pan 4 inches deep made of sheet zinc, and filled with earth; to the middle is soldered a tube of zinc, into which a large bottle fits; the bottle is filled with water to keep the plants placed in it fresh and green; b, outer case, with sides of glass, fitting closely about the zinc pan; c, top, covered with wire-cloth, rabbeted on b, and easily lifted off.

Fig. b. Diagram showing way to make paper envelopes for butterflies.

Fig. c. Envelope folded with butterfly inside.

Fig. d. Stretching board for expanding moths and butterflies. Strips of tracing-muslin are used on this to keep the wings down, paper will also serve the purpose.

Fig. e. Stretching board, showing how wings may be held in place by pieces of thin cardboard.

Fig. f. Showing the way in which the antennæ and body may be held in place with insect pins while the insect is drying.

Setting blocks are most advantageously employed in mounting small species, especially the Hesperiidæ, the wings of which are apt to be refractory. When the insect has been pinned upon the setting board or setting block, the next step is to set 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.” Setting needles may be easily made by simply sticking ordinary needles into wooden matches from which the tips have been removed; steel insect pins will serve as well. In drawing the wings into position, care should be taken to plant the setting needle or pin behind the strong nervure on the costal margin of the wing; otherwise the wings are liable to be torn and disfigured. The rule in setting lepidoptera is to draw the anterior wing forward in such a manner that the hind margin of this wing is at right angles to the axis of the body, the axis of the body being a line drawn through the head to the extremity of the abdomen. The hind wing should then be moved forward, its anterior margin lying under the opposing margin of the front wing. When the wings have thus been adjusted into the position which they are to occupy, slips of tracing-muslin or of paper should be drawn over them and securely pinned, the setting needles being removed.

In pinning down the strips which are to hold the wings in place, be careful to pin around the wing, but never if possible through it. When the wings have been adjusted in the position in which they are to remain, the antennæ should be attended to and drawn forward on the same plane as the wings, and secured in place. This may ordinarily be done by setting pins in such a position as to hold them where they are to stay. Then the body, if it has a tendency to sag down at the end of the abdomen, should be raised. This may also be accomplished by means of pins thrust beneath on either side. Plate E, Fig. e, shows clearly what is intended. When the insect has been set, the board should be put aside in a place where it will not be molested or attacked by pests, and the specimens upon it allowed to dry. A box with shelves in it is often used for this purpose. This box should have a door at the front covered with wire gauze, and the back should also be open, covered with gauze, so as to allow a free circulation of air. A few balls of naphthaline placed in it will tend to keep away mites and other pests. The time which the specimen should remain on the board varies with its size and the condition of the atmosphere. Most butterflies and moths in dry weather will be sufficiently dried to permit of their removal from the setting boards in a week; but large, stout-bodied moths may require as much as two weeks, or even more time, before they are dry enough to be taken off the boards. The process of drying may be hastened by placing the boards in an oven, but the temperature of the oven must be quite low. If too much heat is applied great injury is sure to result. Only a careful and expert operator should resort to the use of the oven, a temperature above 120 F. being sure to work mischief.

When butterflies or moths have been put up in papers or mounted on pins without having their wings expanded and set, it becomes necessary before setting them to relax them. This may be accomplished in several ways. If the specimens have been pinned it is best to place them on pieces of sheet-cork on a tray of sand which has been thoroughly moistened and treated with a good dose of carbolic acid. Over all a bell glass is put. A tight tin box will serve the same purpose, but a broad sheet of bibulous paper should always be put over the box, under the lid before closing it, and in such a way as to leave the edges of the paper projecting around the edges of the lid. This is done to absorb the moisture which might settle by condensation upon the lid and drop upon the specimens. In a bell glass the moisture generally trickles down the sides. Earthenware crocks with closely fitting lids are even better than tin boxes, but they must have paper put over them before closing, in the same way as is done when tin boxes are used. When specimens have been preserved in papers or envelopes these should be opened a little and laid upon damp, carbolized sand under a bell glass or in a closed receptacle of some kind. Papered specimens may also be placed in their envelopes between clean towels, which have been moistened in water to which a little carbolic acid has been added. The towels should be wrung out quite dry before using them. Pieces of dampened blotting paper are even better than towels. The method of placing between towels should never be used in the case of very small and delicate species and those which are blue or green in color. Great care must be exercised not to allow the insects to become soaked or unduly wet. This ruins them. They should, however, be damp enough to allow the wings and other organs to be freely moved. When the insects have been relaxed they may be pinned and expanded on setting boards like freshly caught specimens. It is well in setting the wings of relaxed specimens, after having thrust the pin through the body, to take a small forceps and seizing the wings just where they join the body gently move them so as to open them and make their movement easy before pinning them upon the setting board. The skilful manipulator in this way quickly ascertains whether they have been sufficiently relaxed to admit of their being readily set. If discovered to be too stiff and liable to break they must be still further relaxed. Dried specimens which have been relaxed and then mounted generally require only a short time to dry again, and need rarely be kept more than twenty-four hours upon the setting boards.

The process of setting insects upon setting blocks is exactly the same as when setting boards are used, with the simple difference that instead of pinning strips of paper or tracing-muslin over the wings, the wings are held in place by threads or very narrow tapes, which are wound around the block (see Plate D, Figs 6 and 7). When the wings are not covered with a very deep and velvety covering of scales the threads or tapes may be used alone; but when the wings are thus clothed it becomes necessary to put bits of paper or cardboard over the wings before wrapping with the threads. Unless this is done the marks of the threads will be left upon the wings. Some little skill, which is easily acquired by practice, is necessary in order to employ setting blocks to advantage, but in the case of small species and species which have refractory wings they are much to be preferred to the boards.

The work of mounting small insects which have been relaxed must be done quite quickly and in a cool room or in a moist atmosphere. In a very dry and hot atmosphere the minuter things dry so quickly that difficulties are at once encountered.

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One of the best ways in which to secure perfect specimens is to breed them from the caterpillar, or even from the egg. A stylish and very good cage for breeding is shown on Plate E, Fig. 2. As good a cage as this is not necessary, and the collector will succeed with one or more clean store-boxes covered with a lid consisting of a frame over which gauze or muslin has been stretched. The food-plant on which the caterpillar feeds is kept fresh in bottles or jars. It is important, after the plants have been put into the jar of water, to stuff around the stems cotton or soft paper, so that the caterpillars may not crawl down and, falling into the water, drown themselves. The bottom of the box may be filled to the depth of four or five inches with loam and covered with dead forest leaves. The loam should not be allowed to dry out thoroughly, but should be kept somewhat moist, not wet. A little sprinkling of water from time to time will suffice when done with care. The caterpillars feed upon the food-plant, and finally undergo transformation in the cage into the pupa, and eventually emerge as the butterfly or moth. The breeding of lepidoptera in this way is a fascinating occupation for those who have leisure to attend to it. For more minute instructions in reference to this matter the reader is referred to “The Butterfly Book.” The caterpillars and chrysalids themselves may be preserved in little phials, in alcohol or in a solution of formaldehyde. The latter, however, is not to be recommended, because, although it preserves colors better than alcohol, and does not tend to shrivel up the bodies, it makes them stiff and difficult to handle and examine. The best way of preserving caterpillars is to inflate them. Directions for doing this are contained in “The Butterfly Book.”

THE PRESERVATION AND ARRANGEMENT OF COLLECTIONS

In order to preserve collections of lepidoptera in beautiful condition, light, moisture, and insect pests must be excluded. Light bleaches many species, especially those which are red, brown, or green in color. Moisture produces mold and mildew. Insect pests such as mites, Anthrenus, and Dermestes, the two latter being species of beetles, devour specimens. The receptacles containing collections should therefore be furnished with covers excluding the light, kept in a dry place, and be so tight that insect pests will not enter. However, as an additional precaution, it is well to place in every box or drawer moth balls or lumps of camphor, secured so that they cannot roll about. These tend to deter predaceous insects from entering the receptacles. If by any chance they have entered, neither the naphthaline nor the camphor in some cases will prevent their ravages. In the great collections which are under the care of the writer it is a rule from time to time to go over all the cases and put into every receptacle a small quantity of carbon bisulphide. The fumes of carbon bisulphide kill all grubs and matured insects which may have hidden themselves in the cases, and it is believed that it also tends to destroy the life in eggs which may have been laid in the boxes. Great care should be used, however, in employing carbon bisulphide, as the fumes mingled with the oxygen of the atmosphere form an explosive compound. The work should never be done where there is danger of ignition from an open fire or light. Boxes for the preservation of insect collections are made by many firms, and prices for such receptacles vary according to their size and the materials employed in their construction. All receptacles, however, should be lined at the bottom with cork or some other soft material into which the pins sustaining the insects can be put. We employ in the Carnegie Museum a composition cork covered with white paper, which is made in sheets of varying sizes, according to requirement, by the Armstrong Cork Manufacturing Company of Pittsburgh, Pa., the largest cork-manufacturing establishment in the world. This is the most satisfactory material which is made.

Large collections are advantageously preserved in cabinets, the drawers of which are covered with glass through which the insects may be inspected without handling them. Here again, for the details of the construction of boxes, trays, and cabinets, the reader is referred to “The Butterfly Book,” which may be found in every public library, and is in the hands of multitudes of individuals.

In arranging specimens the scientific order should be followed. The species belonging to a given genus should be placed together. The little labels attached to the pins should give both the generic and the specific name, the locality where the specimen was taken, and the sex, if known. For the purpose of designating the sex naturalists employ what are known as “sex marks,” the male being indicated by the sign of Mars, ♂, while the female is indicated by the sign of Venus, ♀. The inscription Papilio philenor, ♀, means that the specimen is a male, and the inscription Papilio philenor, ♀, means that it is a female of the same species.

The classification of the genera and species should be subordinated further to the classification into families. There are five families of butterflies represented in the United States and Canada. They are the following:

1. The Nymphalidæ, or “Brush-footed Butterflies.” 2. The Erycinidæ, or “Metal-marks.” 3. The Lycænidæ, or “Blues,” “Coppers,” and “Hair-streaks.” 4. The Papilionidæ, or the “Swallowtails” and their allies. 5. The Hesperiidæ, or the “Skippers.”

In every well-arranged collection of butterflies certain drawers or boxes should be set apart for the reception of the insects belonging to these families, and they should be placed under their proper genera, according to their species. Nothing is more beautiful or interesting to those who have a love of nature than a collection of butterflies thus classified and displayed.