Place the setting block on the table, with the top furthest away from you. Proceed to select the various butterflies from your damp collecting-box which will best suit the size of the block, allowing about a quarter of an inch clear from the outer edge on each side. Then, with the forceps, take hold of the upper part of the pin near to the body and firmly drive it in the same leaning position as it is fixed into the body, firmly into the exact centre of the groove. If the pin will not go readily into the block, make a lead for it with a sharp-pointed penknife. Do not be tempted to push down the body on the pin, or your specimens will, on removal from the blocks, be all sorts of heights on the pins, and quite unfit for cabinet purposes. Next see that the shoulders of the wings just touch the edge of the block, so as to place the wings flat, without tilting up the tips. Observe carefully that the bodies are straight and lifted by placing under them bits of paper or cotton wool so as to extend on an even plane with the thorax and wings. Continue placing your specimens until exhausted in number, or until the block is quite full, after leaving a clear space between each butterfly sufficient to lift the wing tips slightly forward of the front part of the head. Then with a sharp penknife, very neatly cut a thin nick in the under edge of the ends of the block directly below the shoulder piece of the centre groove. There should be four of these little nicks. Next get a piece of glazed cotton thread, and tie a knot at one end. Insert this knot in the top left-hand nick, the knotted end being below the block. Very gently, but firmly, bring the thread over the end of the block, close to the shoulder, down the left-hand side closely into the inner edge of the block, catching it in the bottom left-hand nick under the block. This will have had the effect of placing all the wings firmly on that side of the block. Then carry the thread underneath the block into the top right-hand nick and over the end of the block, down the right-hand upper side, over the lower end, firmly fix in that nick and cut off the thread. Great care must be taken to pull the thread over the wings not so tightly as to mark them. A good plan is to push under each upper end of the thread a thin pin which eases it, so as to avoid damaging the top and bottom specimens in the row while setting them into their respective places. These pins may afterwards be withdrawn. Next proceed with a very fine pointed needle to gently lift all the wings into their proper places so as to get the effect of “a well-set butterfly.”
It may be found that the thread is too slack in places to hold down the wings in proper position. That may be obviated by neatly cross-pinning down the thread on either side at intervals between the butterflies.
When all the specimens have been arranged with perfect uniformity, take two slips of tracing-paper, which have been previously cut to fit the length of the block, and each must be three-fourths the breadth of one side of the setting block. Then lay one of these strips of paper on the left-hand side, being very careful to keep just clear of the thread. All the wings will be seen plainly through the transparent paper and can be readjusted if any slip out of position. Next place with the forceps a No. 10 entomological pin firmly through the top and at the bottom of the paper, near the edge next the cotton. Place another between the first and second butterfly on the block, and so on down the row; also, as you go along, place another pin between the outer indentation where the upper and lower wings meet; also put a fourth pin by the tip of the upper wing. These pins should firmly secure the paper over the wings, which, when thus treated on both sides, will dry into the desired position for cabinet specimens. The greatest care must be taken not to allow any pin-point to enter the wing or fringe of a butterfly, or it will be quite spoiled. Next very carefully and gently undo the fastened thread, first taking out any cross pins which secure it. After its removal gently stroke from the body towards the paper on each side with a soft camel’s hair brush any disturbed scales. With practice there should not be the least damage done by the thread, which leaves no mark whatever if moved at once when the papers are firmly fixed. If they should be left on carelessly, or by any mistake, the threads will be certain to mark every butterfly, to their complete disfigurement.
Keep the blocks which contain the set-out butterflies in a dry cupboard or other safe place. When thus drying they fall an easy prey to earwigs, wasps, ants, cockroaches, and such like “small beasts,” which will strip off all the bodies on a block in a single night. They should not be exposed to too bright a light whilst drying on the blocks, or they often suffer in colour. When single specimens have to be set out it is easy to work the thread by putting a pin through the knot and holding down the other end with the left-hand forefinger until the paper is fixed, and then treating the other wings in like manner.
It is advisable to leave the butterflies on the blocks for about a week, though the surest test is to touch the body gently with a pin, and if quite hard, it is safe to remove the insects to a store box without fear of the wings springing. After removing the butterflies, pass over the surface of the block some hard substance, such as the back of an ivory-handled knife, to rub down any little roughness made by the pins on the surface, where the wings are placed, when setting any fresh insects on the same block.
Most of the butterflies are easily reared through all their stages, from the eggs up to the perfect insect. This is by far the most interesting part of the study. Until within the last few years, when the writer of these chapters pressed some of his friends to look more closely into the life histories of our common butterflies, it was the custom of some naturalists to sneer at “butterfly-catchers.” Since then a wonderful book has been published on the butterflies of the Eastern portion of North America by Mr. Scudder, and all these scoffers must feel very small when they see such splendid science in the study of butterflies. Now, many people, who never throughtthought of rearing a butterfly, are giving careful attention to them in all their stages.
Several kinds of butterflies are readily induced to lay their eggs in captivity when carefully managed. Various species differ much in this—some may be depended upon with certainty, such as the “green-veined white” (Pieris napi), which will deposit its eggs at night upon a piece of watercress, under the influence of a warm room, and the bright light of a paraffin lamp. This species, however, is quite an exception, for, as a rule, every attention should be given to copying their natural surroundings as closely as possible. A good plan is to have ready planted in a large flower-pot a plant of the food of the particular species from which it is desired to have eggs, or, as they are called by the entomologists, the ova—that being, as you know, the plural of ovum, the Latin for an egg. Having got your plant nicely established in its flower-pot, buy a piece of wire-netting, about a foot wide, and bend it round so as to fit just inside the flower-pot. By cutting the wire so as to overlap a little, it is easy to twist or hook the ends, so as to make a cylinder to just fit inside the pot. Then cover this with very open muslin all round and over the top, neatly stretched, so as not to look untidy or to stop a single ray of sunshine which can get through. Having had several of these cages prepared, they may be used at the moment when you bring home the freshly-caught females.
The sooner the female butterflies are placed in the cage the better, for if they remain too long in the pill-box they are apt to get too dry, and so never recover enough to deposit their ova. After firmly tying the cage to the pot, do not disturb them when once in the cages, so long as they are alive; but leave them out of doors, where they get all the sunlight or rain. If the plant be watered, that is best done by soaking the flower-pot in water up to two-thirds the height of the soil, and not by removing the cage. Still, in dry weather it is best to sprinkle the cage with water, so that the captive may drink, which they often require to do.
Another way, especially in the case of small butterflies, is to use large glass jam-pots, with a piece of muslin tied over the top. In these pots should be a little sprig of food-plant in a small bottle of water, and also a bit of damp sponge to keep up a moist atmosphere, without which there will rarely be any eggs. The pots may be placed in the sunlight in a room near an open window, but care should be taken that the glass does not get too hot, or both parent and eggs may be killed. When the eggs hatch, never, if possible, touch, except with a camel-hair brush, the young caterpillars—or larvæ as they are scientifically called, that being the plural for larva, a single caterpillar. Pupa is the singular, and pupæ the plural, for the chrysalis; imago the singular, and imagines the plural, for the perfect insects or complete butterflies. These scientific terms are quite easy to learn, and are the best to use when referring to the various stages of insects generally.
In selecting females for depositing ova, take those which are a little worn, and not too recently emerged from pupæ, as they are the more likely to produce fertile eggs.