Part 6

Card points are small triangles of cardboard or plastic pinned through one of the sides and crimped over at the opposite apex; a spot of strong glue is put on the angled tip, and the right side of the insect is pressed against the glued surface, fig. 14. The slant of the crimp depends on the angle of the insect's side; the desired product is the insect mounted with its top surface horizontal and its head forward; legs, wings, and antennae should be in view and as little of the body as possible hidden by the glue or card point. Very little glue should be used; a small amount holds well and gives a better specimen for study than a large amount. The points may be cut uniformly with a hand punch, and they should be about three-eighths inch long. Good material for making these points is 2-ply Bristol board.

Minuten pins are short, extremely delicate steel pins, fig. 14d. One of these is thrust through the body of the insect and into a small piece of cork, pith, or similar substance, which is in turn pinned in the regular way a card point is. This method is especially desirable for tiny moths.

Insects Hard to Pin.--Wasps, lacewings, damselflies, and similar insects have an abdomen that sags readily when the specimen is killed and pinned. This unwanted drooping can be prevented in three simple ways. (1) Stick the pinned insect on a vertical surface of a block so that the body by its own weight dries in normal position. (2) Pin the insect on a horizontal surface and run a stiff paper on the pin beneath the body in such a way as to support it in a natural position until the insect dries. (3) Brace the abdomen by crossing two pins beneath it and thrusting them into the block, allowing the specimen to dry in the angle of the cross.

Crane flies are unwieldy and so are best pinned on a double card point mount, fig. 15. The legs should be directed away from the pin to avoid breakage in handling.

Spreading Board for Moths and Butterflies

Moths and butterflies should have their wings spread before being put into the collection. To do this well, it is necessary to have spreading boards that are accurately made but that are not necessarily complicated or expensive.

Construction.--A convenient board for medium-sized insects can be made at home of the following materials:

1.--A hardwood base, 4 x 12 x ¼ inch. 2.--Two hardwood end pieces, 4 x ¾ x ½ inch. 3.--Two softwood top pieces, 1-7/8 x 12 x ½ inch, with the top surface planed at an angle, so that the thickness at one edge is ½ inch and at the other 3/8 inch. 4.--Two flat cork pieces 1 x 11 x ^3/16 inch.

Nail the top pieces to the ends so that the slanting surfaces of the tops are uppermost and the narrower edges parallel and one-quarter inch apart, fig. 16. Glue one strip of cork beneath the top pieces, covering the opening between and fitting snugly at each end. Glue the other cork piece flat to the upper side of the base, lengthwise along the middle, and extending to within one-half inch of each end. Finally, nail the base across the bottoms of the end pieces, so that the two corks face each other.

Use.--Before spreading the specimen, relax it as described under "Relaxing Boxes and Jars." Then pin it, keeping in mind fig. 12 and the directions given under "Preservation by Pinning." Thrust the pin, with the insect on it, through the upper cork of the board and into the cork on the base. Insert the insect body in the groove so that the wing bases are level with the near edge of each top piece. Hold the wings at the top level by two narrow strips of paper and pull them forward until the hind margin of the front wing is at right angles to the body axis, and the front margin of the hind wing is just under the front wing, fig. 16. Pin the wings temporarily in this position by inserting a pin, size 0 or 00, near the front margin at the base of each wing. When the wings on both sides of the insect are thus adjusted, lay strong pieces of paper over them and pin them down securely with large pins inserted close to the wings but not through them. Here you may use large common pins, but still better are the large-headed dressmaker's pins about 1¼ inches long. Finally, remove the original adjusting pins and put the specimen in a dry, pest-proof container for 2 or 3 weeks. It will then have set sufficiently to be removed from the board.

For good results, spreading boards with grooves of various widths are necessary; a specimen should be spread on a board with a groove that fits the body. The width of the top pieces should vary to accommodate different wingspreads. The slope of the top pieces should be about as described.

Preservation in Fluid

Caterpillars and other immature stages of insects should be preserved in 80 per cent grain alcohol. Caterpillars, grubs, and maggots should first be heated 5 to 10 minutes in water just at the boiling point. This treatment sterilizes the specimens and prevents their discoloration by bacteria in the digestive system.

Many soft-bodied adult insects, including bristletails, springtails, stoneflies, and caddisflies, also should be preserved in fluid. If pinned, they shrivel to such an extent that few identifying characters can be seen. The preserving fluid in the vials in which insects have been placed should be changed at the end of the first day or two.

Some hard-shelled insects may be preserved in fluid. Ants and beetles may be thus treated temporarily and later pinned and dried.

HOW TO LABEL THE SPECIMENS

To be useful to the entomologist and others interested in the scientific relations of insects, as well as to furnish the collector with a complete record of his hours in the field and make more valuable the work he has already accomplished, the specimens should be labeled. The important information to be put on the label of each specimen is the locality and date of capture, but greater scientific value will be attached to the specimen by adding the name of the collector and the host on which the insect was found, or the particular habitat in which the insect was caught.

Labels should be made of a good grade of white paper stiff enough to stay flat when pierced and pushed up the pins. A very satisfactory high quality paper is available under the name "substance 36 ledger." The labels may be printed by hand with a crow-quill pen and black India ink, or they may be purchased completely or partially printed from a biological supply house. They should be as small as possible and of nearly uniform size. They should be pushed up the pins, fig. 14, not too near the specimens, and they should project from the pins in the same direction as the specimens. To keep the labels small, yet to include all desirable information, it is often well to record the locality, collection date, and collector on one label, and the host plant or other pertinent information on a second label, fig. 14.

When the specimen is identified, its name should be recorded on still another label, which should be kept low on the pin. Sample identification labels are illustrated by the bottom labels in fig. 14.

HOUSING THE COLLECTION PERMANENTLY

After the specimens have been pinned and labeled, they should be housed in boxes or cases having a soft bottom or inner layer that will allow easy pinning. Such housing not only insures the safety of the collection but makes for easily handled units once the specimens have been named.

Insect Boxes

Several satisfactory types of boxes for housing insect specimens may be bought from commercial supply companies. These are usually much better than boxes of home construction, being more nearly dustproof and pestproof. Homemade boxes, however, are quite practical for the beginning collector, due to their ease of construction and extremely low cost. Cigar boxes 2 inches deep or more make ideal insect boxes if a layer of cork or balsa wood or two layers of soft, corrugated cardboard are glued in the bottom. Other wooden or cardboard boxes may be provided with such a bottom pinning surface and used for storing specimens. Boxes of this type, however, afford the specimens no protection against pests, and great care must be exercised in keeping the boxes fumigated.

Manufactured boxes, cabinets, and cases may be selected from catalogs that various scientific supply firms send free upon application.

Precaution Against Pests

Certain insects, such as flour beetles and carpet beetles, feed upon dried insects, and unless precautions are taken these may entirely destroy a collection. To guard against them, various chemical repellents may be placed in the boxes containing specimens. Naphthalene, of which ordinary mothballs are composed, is one of the best repellents. A few mothballs may be put in a cloth bag pinned securely in one corner of the box, or the heads of common pins may be inserted into naphthalene mothballs, and the points stuck in the corners of the box, fig. 17.

Naphthalene is chiefly repellent in action; its odor keeps out pests, but, if they are already in the specimen boxes, naphthalene will usually not kill these pests, and some other substance must be used.

Paradichlorobenzene, called PDB, is a good fumigant to use on pests in the collection. It should be used in a nearly airtight container, such as a tight trunk, bin, or case, at the rate of 1 pound of PDB to 25 cubic feet of space. The boxes of specimens, with lids open or removed, should be placed in the container, the fumigant scattered or spread on a piece of cloth or paper above them, and the container sealed for about a week.