In removing an insect from a block, draw a sharp knife across the back of the block and lift off all the cotton at once. If the body of the specimen being set needs support, as sometimes happens, give the cotton two or three cross turns, and with your setting-needle raise the body on to this as shown on [Plate VI.] One hint more: See that your lines diverge from near the body at the bottom to near the tip of the wings at the top; the reason for this is that if you have to slip the wing forward under a turn of the thread it will not be damaged if the thread is arranged as indicated, whereas if your thread be laid on, say, from the outer bottom corner in towards the head, it would then scrape the wing, and be sure to remove some of the scales, thus damaging the specimen. The correct method is shown on [Plate VI.] With ordinary care and usage a good cop should last a year or two.
After your insects are set, by whatever method, they need to be put aside in a dry, airy place to harden, and be secured against the ravages of mice and spiders. For their better protection, it is usual to place them in a “drying case,” which need not be an elaborate affair. My drying case was constructed out of an empty box obtained from the grocer; judging from the legend on the outside it had once contained tins of preserved apples. This is set up on end with the bottom removed and made into cross shelves. Light muslin cloth is tacked on in place of the bottom, so as to admit air but exclude dust. On the front, where the lid was originally nailed, is a hinged frame, covered with the same material, acting as a door. This drying house is not exactly pretty, but it has served its purpose admirably for many years.
A representative of the larva of each species is now considered essential to a complete collection of butterflies, and it is rendered even more perfect if egg-shells and chrysalis cases can also be included.
We now have a fairly easy and reliable process for preserving larvæ, a process which any aspiring young collector can carry through without much trouble or expense. It is really very simple and costs little. True, one can purchase apparatus specially made for the work for ten, or even five, shillings, but equally good results can be obtained with the expenditure of a few pence and a little ingenuity. I strongly advise young folk to make their own apparatus; by so doing they develop resourcefulness, and a handy youngster is not likely to make a failure of his life.
In the first place you will need a hot-air chamber. Any empty toffee-tin will serve this purpose; one somewhere about 6 inches long by 4 inches in diameter will be a handy size. Get a piece of copper or soft iron wire, such as milliners use; give the wire two or three turns round the tin, twisting it as tightly as you can: then give the two free ends a turn or two round a gas-bracket near the burner, so as to bring your tin, with the open end next you, just over the burner. Or you may mount the tin over a spirit-lamp, in which event you will not be troubled with soot gathering on the outside of your oven. You now have an oven which you can make as hot as you want it by regulating your flame; you will soon discover the right temperature in which to dry a skin quickly without burning it. The skins of small, thin-skinned caterpillars dry very quickly, whilst those of large moths, such as the Oak Eggar, dry more slowly even with more heat.
Your next requirement is a glass blowpipe: this you can purchase at the chemist’s for a copper. Ask for a glass tube about a foot long and a quarter of an inch in diameter. Now, this tubing is made of a very soft and pliable kind of glass, and by heating it over a flame you should have no difficulty in drawing out one end of the tube into a fine point, not too long and not too abrupt; the illustration ([Plate VII.]) will show you the right length of the point. Hold the end over the gas-jet, keep turning it round, and in a minute it will become red and soft; remove the end of the tube from the flame, grasp it with a pair of forceps, and gently and steadily pull the heated portion until it is drawn to a point of the required length. Nip off the part you caught with the forceps, and your tube is ready. Or another way is to heat the tube in the middle, and pull the two ends apart; this will give you two blowpipes, and you can make a fine point to one for small caterpillars and a wider aperture to the other for large ones. I used to know a friendly chemist who would “point” as many tubes as I wanted at his Bunsen burner in a few minutes. To complete your blowpipe, you will need about 2 inches of a watch-spring—any watch-repairer will give you a broken spring. The photograph on [Plate VII.] shows how the piece of spring is placed and used; it is bent to the required shape while heated, and bound in position with fine copper wire. The wire I use is the same as that required for mounting dried larva skins; it can be obtained at any shop where electrical appliances are sold; it is an extremely fine wire covered with green silk thread.
Your larva-preserving outfit is completed with a sheet of blotting-paper and an ordinary lead pencil. I will now describe the process.
PLATE 4.
1. [Clouded Yellow] (Male)
2. [Brimstone] (Male)
3. [Silver-washed Fritillary] (Male)
4. [Dark-green Fritillary] (Male)
5. [High Brown Fritillary]
6. [Queen of Spain Fritillary]
7. [Small Pearl-bordered Fritillary]
8. [Pearl-bordered Fritillary]
9. [Greasy Fritillary]