Carry the empty pill-boxes in the right-hand side pocket of the coat, transferring them to the left-hand side as filled, so that the full and empty boxes never get mixed in the pockets. Having safely netted the butterfly, place the net on the ground, and take a suitable sized pill-box in the right hand. Remove the lid, which is to be placed in the ball of the hand loosely under the bottom of the pill-box. This leaves the left hand free. Then insert the right hand into the net, and cover the butterfly with the pill-box, holding it with the left hand from the outside of the net, carefully keeping the gauze tightly over the box with the left forefinger. The right hand, which is now free, still contains the lid of the pill-box, which gently place over the butterfly, slowly drawing out the gauze remaining between the lid and the box. Quickly transfer the filled box, which should contain only one specimen, into the dark left-hand pocket. Most butterflies will at once become quiet in the dark, if it is not too hot. As opportunity occurs, it is best to transfer them to the hand-bag, which should be left near, under the shade of a bush in a cool place. By this means every specimen should be so boxed without the apparent loss of a single scale from their wings. Only take good specimens—don’t be tempted to get a quantity, but rather go in for fine quality. Especially avoid any which are chipped, rubbed, or otherwise unfit for cabinet specimens. It is a great mistake to take imperfect specimens, for they give just as much trouble as the finest, and are never of use either for the collection or for scientific purposes. If it is not convenient on arrival home to immediately set out our captures, they should not be killed, but placed in the biscuit-tin or left in the bag just as they are, in a cold, dark cellar, or like place, where they will be all right for a couple of days or more, remaining perfectly still.
Having brought home our captures we now produce the biscuit-tin. This is to be used for the “lethal-chamber,” where the specimens are to be sent to sleep, but not to “awake refreshed.” The processes of by-gone times for killing butterflies for collections have been many, the most primitive, perhaps, being pinching the under side of the thorax, or that part of the body to which the wings are attached. Doubtless, there are in the various collections of butterflies, large numbers of fine specimens which have been so killed; but it is an objectionable plan, because even when skilfully executed, the specimens are more or less mutilated in the structure, and are consequently difficult to set out with accuracy. We are almost certain by this method to break off a leg or two, or otherwise render the specimen imperfect. Chloroform is used by some people to kill their butterflies, but it is unsatisfactory, for it often renders them very rigid and too stiff to immediately set out, which is a great disadvantage. Much the same may be said of the fumes of cyanide of potassium, which constitute the active properties of the “killing bottles” sold by the dealers. It is, however, always wise to keep one of these bottles in the hand-bag, in case something very special is to be immediately stupefied. It must, however, be a good large bottle, with wide mouth, for it is needed generally for the big butterflies, such as the larger fritillaries, purple emperors, and the like in size and strength. There is nothing, however, so good for obtaining perfect specimens as boxing the butterflies in the nets, conveying them home in a dark hand-bag, and then killing them in a biscuit-tin with the fumes of strong liquid ammonia. It is best to buy a four-ounce tightly-stoppered squat-bottle for keeping the ammonia, which, when not in use, should be placed out of the light, in a drawer or cupboard, taking care the stopper is tightly fixed. In buying the ammonia ask the chemist for that with a specific gravity of .880, which is commonly kept by them. Some chemists will try to persuade the buyer that it is not safe, so as to supply a weaker article; in which case don’t trade with him again, for anything weaker will not only not kill the butterflies, but simply irritate them into knocking themselves into small pieces. Now to proceed. We place about a large teaspoonful of the liquid ammonia into a little cup, or better, in a small mustard-tin lid, taking care to keep our eyes and nose clear of the fumes. Place this as quickly as possible at the bottom of the biscuit-tin, and over it loosely a piece of paper, so as to let out the fumes, but to stop the pill-boxes from falling into the fluid, and so doing damage to box and contents. Then place the boxes containing the butterflies into the tin and tightly close the lid and leave them for not less than half an hour, or better still, a little longer. The boxes thus placed may be left overnight and opened next morning, if more convenient; but in that case it is best to put in with them a small piece of damp sponge about the size of a walnut, so as to keep the specimens from getting too dry. This damp atmosphere should also be there when the butterflies are stored away alive in the dark, for a day or two, as described already.
On opening the lid of the biscuit-tin containing the ammonia and pill-boxes, be careful to keep your face well away, or the puff of vapour may be very painful. There is no danger whatever to be feared from the use of ammonia in this manner, but still it may lead to temporary discomfort, such as pain in the eyes and loss of breath for a moment.
Having removed the lid proceed in the following manner: First place on the table before you a sheet of white paper or a blotting-pad. By your side on the table have a small tea-tray, or other flat receptacle. Take out of the tin one of the top pill-boxes, open the lid, and shake out the butterfly on the sheet of paper in front of you. Then put the lid of the pill-box with its top turned downwards, on the tea-tray, and place the remainder of the pill-box, sideways within the lid. The object is to let the air get to the inside of the boxes, so as to evaporate the ammonia still remaining about them, or the next butterfly to occupy the box will object to the stale fumes of “smelling salts,” and probably knock itself about in consequence. The boxes may be thus all emptied and left to air, which will not require much more than an hour, or even less, if the tray be placed in the sunshine near an open window. By placing each box sideways in its lid, the boxes and lids all fit one another, and do not get tiresomely mixed.
In shaking out the butterflies place them in rows neatly on the paper, so that you know which was the first to leave the boxes, for that row should be the first pinned, having been exposed longer to the fresh air, to permit the ammonia attached to them to evaporate. If pinned too soon, the ammonia is apt to affect the metal of the pin and make it brittle where it passes through the body of the insect. The action of this gas is most peculiar on the colours of some insects, especially on that of the small heath butterfly, marbled whites, or some of the blues. When seen for the first time one is horror-stricken, and apt to exclaim that the specimens are ruined with the nasty stuff. This, however, soon all passes away as the ammonia evaporates and the normal colours reappear in all their former beauty. Some collectors rail against ammonia, using themselves some worse killing medium. There is no other such medium which will allow of one, after pinning the insect, to move it up and down quickly in the air with the effect that the wings are as flaccid as though the specimen were alive. It leaves not the slightest trace of rigidity, which is of the highest importance for quick and successful setting out.
The next proceeding is one which requires delicate handling and touch, which can only come with practice. It is pinning the insects. To do this there is only one way which permits of the specimen being afterwards exactly set out, and that is, the “proper way.” Any deviation from it, simple as it is, leads to all sorts of trouble and vexation when we come to set the butterflies out on the blocks. Take the butterfly—with the wings closed together over the back, so that the under side only can be seen—between the left hand first finger and thumb. Touch it deftly, but firmly, holding no more than is necessary of the under side of the thorax, where the legs are fixed. Be very careful not to break off any of the legs, or rub off any scales from the body or legs. A small pair of curved forceps are of great use in delicately placing the butterfly in position between the fingers. The proper position allows of the wings to more than half open, when gently blown upon with one’s breath. Then choose a pin of suitable size, rather a little large than otherwise, and pass it through the centre of the upper part of the thorax, just where the two front wings meet. Mind it is exactly in the centre and so placed that the pin’s head leans somewhat forward when the pin is fully in the body. Pass the pin well through the body, so that at least one third of its length is clear of the underside of the butterfly, and all as nearly as possible the same distance through.
When we have pinned the specimens, we proceed to set or spread them out on the blocks to dry. In selecting these, say they are for butterflies, do not get the slot groove down the centre too wide, as is needed for the fat-bodied moths. Those blocks used in this country are generally somewhat rounded on each side where the wings are to rest. This is called “round-setting” in distinction to “flat-setting,” which means that the wings, when quite dry, remain set out flatly at right angles from the body; while round-setting leaves them drooping at the tips in an unnatural manner. Round-setting is considered, outside the British Islands, an insular abomination. It was the style, unfortunately, adopted in this country with the dawn of the present activity among British entomologists, and everybody knows how difficult it is to change even such a simple fashion as the round-setting of butterflies. Simple as the matter seems at first sight, it has contributed more than any other cause to the generally shameful ignorance which prevails among British entomologists of even the butterflies of the Continent of Europe outside our islands. Because they can only be obtained from abroad “flat-set,” most of our collectors would hardly look at a “foreign” butterfly; and so the study of the British species has been blocked for years, entirely from this cause, which fostered so largely the prejudice in favour of “British specimens.” A “British” Camberwell Beauty is now worth a sovereign, if taken in Britain, although it doubtless flew over from the opposite Continent; but the same specimen, if taken in France or Belgium, would not be worth sixpence to a British collector. Now all this is wrong and should not be. Of course, it is quite right to know what does occur in our country, but there is no need for these absurd differences in value of the specimens, whether taken in Britain or on the mainland of Europe. It leads to fraud, and it is sad to think that some professional dealers have actually made more than comfortable livings, chiefly by inducing young or inexperienced people to pay long prices for “British” specimens which were perhaps captured in Germany, where they were set on rounded blocks, sent out for the purpose to deceive English people, because they were “round-set” and pinned with Birmingham-made pins!
Another result of this insular prejudice is that some species of butterflies very closely allied to others have been overlooked for want of familiarity with another Continental species. A case of this kind was the cause of our last addition to the British list being so long overlooked. There was this butterfly, quite common, year after year, within twenty miles of London, and flying over fifty miles of country, overlooked; all because of our want of knowledge of even the commonest European species.
We therefore recommend the flat-setting, and if the new generation of students of butterflies will adopt it, the round-setting style will disappear in a very few years.
The blocks should be covered with very fine cork, or may be of soft wood, if the steel pins can be obtained. Then they would be cheaper, as the cork covering adds much to the expense, besides being always unsatisfactory, in consequence of the holes in the cork, which hold mites and such vermin.