Instructions for collecting and preserving various subjects of natural history; as animals, birds, reptiles, shells, corals, plants, &c. Together with A treatise on the management of insects in their several states; selected from the best authorities. By E. Donovan,:
Donovan, E. (Edward), 1768-1837.
Page  40

THE LAST, OR PERFECT STATE.

COLEOPTEROUS INSECTS, OR BEETLES.

THE preservation of this order of Insects, is attended with very little difficulty.

If you drop them into scalding water they die in an instant, but the moisture they imbibe can never be sufficiently exhaled to prevent mouldiness, after they have been a short time in the cabinet.

The best method is to enclose them in a small chip box, and kill them by exposing the box to the heat of a fire; this treatment will rather absorb, than add to the superfluous juices of the Insect, and greatly contribute to its preservation.

Those of the Meloe genus have soft tender bodies which shrivel after death; to preserve those, make an incision at the extremity of the abdomen, probe out the entrails and fill the cavity with fine tow.

Page  41Several foreign species of Cassida, and many other coleopterous Insects, are beautifully variegated with a golden colour that dies with the creature; if you plunge them into well rectified spirit of wine, when alive, they soon expire and retain their golden appearance; but if taken out and dried, that brilliance will be irretrievably lost.

The Chinese seldom take care to display the parts of their Insects after the European manner; those we receive from China are stuck on long needles; if Beetles often through one elytra, so that the membranaceous wings are entirely concealed.

If the Insects require only a little relaxation to extend the parts, use a camel's hair pencil moistened with spirit of wine; but if this should prove insufficient, fix them on a piece of cork and float them in an earthen pan half filled with water; it is better to cover the pan with a damp cloth, and the Insects will be so limber, after a sew hours, that they may be reset in any position.

Large Beetles are usually stuck through one of the shells, as at FIG. 5, PLATE II; but smaller Insects are better if displayed on a small piece of card, as at FIG. 6, PLATE II. (they must be fixed to the card with strong gum); or they may be pierced through the head as at FIG. 7, PLATE II.

Insects of the hemiptera order, as Cimices, &c. may be treated in the same manner.

Page  42

LEPIDOPTEROUS INSECTS, AS BUTTERFLIES, HAWK-MOTHS, AND MOTHS.

IT is usual to put two specimens of each species of the Butterfly kind into the cabinet, one to display the upper, and the other the under side; for the under side is much more beautiful in most species, and differs entirely in appearance from the upper side.

Sphinxes and Moths are generally disposed in pairs to shew the male and female, and as their under sides are seldom very beautiful, only their upper sides are shewn.

Except a few species, Moths constantly conceal their under wings when at rest; but collectors sacrifice the propriety of their remain∣ing in a natural position, in order to display the under wings.—It is advisable to have one of every kind in a natural posture, as that will often essentially assist to determine the family of the Insect.

Provide a quantity of card braces, made in the same form as that represented at FIG. 8, PLATE II; and a board of a convenient Page  43size, covered with soft cork; it must be perfectly even on the sur∣face, and papered; this is termed the setting board.

For small Moths it is only necessary to put the pin through the thorax and they die in a very short time; but for larger kinds, the pin should be dipped in strong aqua fortis before it is put through the Insect.

It is very difficult to kill the largest kinds of Moths and Sphinxes:—select a large pin (comparatively for the size of the Insect) and dip it into aqua-fortis as before, but immediately that the pin is forced through the thorax withdraw it, and put a drop of aqua fortis into the wound; should this prove insufficient to kill it, put the point of the pin through a card, and hold it in the flame of a candle until it becomes red hot; this will kill the Insect immediately, and the card will protect it from being injured by the flame.

The Moth is then to be fixed on the setting board, and the braces are to be applied in the manner shewn at FIG. 9, PLATE II. The wings are to be carefully displayed by means of a large pin, and the braces put close down to prevent their return to the natural position.—Note, All Insects must be set while they remain limber, for if the parts stiffen they are apt to snap; they may be relaxed by floating them in a pan of water.

Insects should remain beneath the braces on the setting board until all the aqueous moisture be evaporated, or the wings will start from their position, and the bodies turn black, or mouldy; they should be placed in a dry situation, and be covered with gause for Page  44the admission of air for the space of a month at least, before they are put into the cabinet.

It is proper in this place to caution the young beginner not to at∣tempt to kill the Insects by fumigations of sulphur, &c. a practice too frequent with persons of this description, for should be by this means deprive the creature of its life, he will also deprive it of its beauty: It is even doubtful whether many may not survive the operation.

M. Lyonet placed several of the large Musk Beetles, probably the Cerambyx Moschatus, under a glass where he had been burning sul∣phur, and which he kept burning while they were there; and though the vapour was so thick that he could not discern them, and that he kept them therein more than half an hour, they did not seem in the least incommoded*.

Some Moths are very liable to change colour when placed in the cabinet, and particularly those which collectors term full-bodied; an oily matter is common to all Insects, but those are charged with a superabundance. It appears at first in spots on the body, but gradually pervades every part; in some it will even descend into the wings, and then an obliteration of all the tender marks and beautiful specklings is the least that may be expected, if a total change of its colours, to an uniform dirty brown, does not ensue. Hence it is that many of the Linnaean descriptions of In∣sects appear defective to such as breed them; we not unfrequent∣ly read, body black, though we know that part of the Insect is Page  45white in every specimen that is not greasy; the body of the Satin Moth* is perfectly white when fine, but after it has been killed some time, it becomes black in parts; the body of the Burnet Sphinx is of a very brilliant blue colour, with yellow bands on every annulation, when alive, but changes to a velvety black soon after the Insect dies; the same is observed on the body of the Currant Sphinx; and every part of the body of the Hornet Sphinx§ changes to a jet black, after being some time in the cabinet; although when alive it is a very bright yellow, with a band of purple. Hence also it is that some specimens of very common Insects are valuable, by having preserved their proper colours uninjured.

Various methods have been tried to extract the grease from the Moths, but a preventative should always be preferred.

If the grease has not spread into the wings, the Insect may some∣times be cured, but it will be very difficult, if not impossible, to eradicate the grease which has settled in patches on the wings.

Large Moths are to be opened in a strait line along the under side of the body, the entrails, &c. taken out, and the cavity filled with fine tow or cotton.—Note, This should be performed soon after the Insect is dead. The most delicate specimens may be preserved entire by this means; we have some very valuable Sphinges, Moths, &c. which were collected by an intelligent person in North America; they retain their colours to the utmost degree of perfection, and have only been prevented from changing black by this simple pre∣paration.

Page  46Sometimes it will be proper to break off the body close at the thorax, and substitute the body of another Insect which nearly re∣sembles it, and which is not so liable to change.

The method which is most successful for recovering the original appearance after the Insect has become greasy, is to powder some fine dry chalk, on a piece of heated iron; cover the chalk with a very fine linen cloth, and thereto apply the under part of the body of the In∣sect: the heat of the iron dissolves the grease, while the chalk ab∣sorbs it, and the linen cloth prevents the chalk from clotting to the Insect. This process may be repeated several times if the grease is not entirely eradicated by the first attempt. Always-observe to exactly attemperate the heat of the iron.

They may be baked in a slack oven, with the chalk placed to ab∣sorb the grease, without any considerable injury to the colours.

Some collectors open the bodies of large Moths, take out the en∣trails, and fill the cavity with fine dry powdered chalk.

MINUTE MOTHS.

TINEA, TORTRIX, ALUCITA, &c.

Much experience, and considerable care, with a light, but steady hand, are necessary for the management of minute Moths on the setting board; it will be equally useless and impossible, to enter into a minute detail of every trivial circumstance that must be attended to, we shall therefore give a general sketch, and leave the rest to the ingenuity of the operator.

First, the fans of the clappers, or forcepts, or the fowling-net if you prefer it, must be covered with silk gause, of a very soft and Page  47delicate texture, and as the slightest friction will obliterate the beau∣tiful specklings, or raised tufts that are so profusely bestowed by the hand of nature on this most elegant tribe of Insects, you must be extremely careful when you press on the thorax not to crush it more than you can possibly avoid; or if you have it between the fans of the forceps, put the pin through the thorax while the creature is confined in that situation.

The next care will be to procure pins of such a degree of fineness, as not to injure or distort the wings of the Insect; the smallest sort of lace pins will do very well for most kinds, but there are some so extremely minute that even those would be too coarse. If you have pins made purposely for Insects of this kind, let them be about an inch in length, and have them drawn as fine as possible.

When the pin is put through the thorax it must be managed with the greatest dexterity, and be exactly in the center, as the least va∣riation to either side will break the nerves of the anterior margin of the upper wings, which will immediately start, and can never be replaced in a proper position; if the pin is placed too high, it will sever the head from the shoulders, and by being too low, the under wings also will break off or start from their true position; it may be managed better with the assistance of a magnifying eye glass.

The braces are to be made of the same form as those which are used for larger Insects, only smaller in proportion; and instead of making them of stiff card, or pasteboard, they may be small slips of vellum, or stout paper that has been hot-pressed. You must brace them immediately after you have put the pin through the thorax, for if they are permitted to stiffen, they cannot be relaxed so well as larger Insects.

Page  48Minute Moths are to be found in winter as well as summer; it would be scarcely imagined, nay reason would deny, did not experi∣ence prove, that when the frost is so severe as to entirely subvert the appearance, and almost annihilate the existence of all the vegetable productions, within the verge of its influence, myriads of those deli∣cately formed creatures brave the inclement season, and exist secure∣ly within those habitations they have the address to construct.

A very skilful Entomologist informs us that having occasion to go into the country when the cold was intensely severe and the snow deep, he collected in a few hours a vast number of minute Insects of the Coleoptera, Hemiptera, and Lepidoptera orders; and though his collection was then very considerable he selected thirteen new species, and among them several which he has never found, but when the weather has been very cold as at that time.

It is proper to observe, that those Insects usually shelter among the moss, and other extraneous matter that grow on the trunks or branches of trees, or beneath the rotten bark. Gather the moss, &c. into a box, or tin cannister, and shut it close to prevent the escape of those Insects, that may revive by the warmth; when you have an opportunity to examine them, spread a sheet of writing paper on the table, and place a lamp, or candle, with a shade of transparent, or oiled paper before you, so as to weaken the glare; then separate the moss, and shake it loosely in your hand, and you will perceive many Insects fall down on the paper; if they are so minute that by thrusting the pin through the thorax they would be damaged, fasten them with gum water, or some glutinous varnish, to small slips or pieces of paper.

Page  49

NEUROPTEROUS, HYMENOPTEROUS, AND DIPTEROUS INSECTS.

AMONG those of the neuropterous order are included the Libel∣lulae, a most elegant tribe of Insects, but very difficult to preserve. The colours on the body are exceedingly brilliant in some species, but inevitably change black within a few days after death, unless the collector is particularly attentive to their preparation.

They are extremely tenacious of life; we have seen one of the larger kinds live two days on the pin, and even shew symptoms of life twenty-four hours after being deprived of its head.

The most expeditious method of killing those creatures, is to run a red hot wire up the body and thorax, for they will live a considera∣ble time in agony if you attempt to kill them with aqua-fortis as before directed for the Moth tribe.

After they are dead, clean their bodies on the inside with a little cotton twisted to the end of a wire, and put a roll of white paper into the cavity, or fill it with cotton; in most species this will not only admirably relieve the colours, but preserve them from chang∣ing black.

Page  50Note, Those kinds only with transparent skins will require this preparation, as the L. 4. maculata, &c.

Some of the foreign Insects of those orders appear to the greatest advantage in spirit of wine, but whenever the usual method will suffice, it should be preferred. They are all to be stuck through the thorax, and observe always to put the pin so far through, that when it is stuck near a quarter of an inch into the cork the feet of the In∣sect may only touch the surface.

The wings are to be displayed with cramps as usual.

Page  51

APTEROUS INSECTS.

MANY kinds may be preserved in spirits, or in the same manner as coleopterous and other Insects; but among those we can include very few, if any, of that extensive genus ARANEA (Spiders), no method having been hitherto discovered whereby they may be pre∣served in their natural colours, for however beautiful they may be when alive, their bodies shrivel and their teints become an obscure brown, soon after death; and as the moisture exhales, the size of the body diminishes, very little more than the skin of it remaining when the creature is sufficiently dry to be placed in the cabinet.

Spiders cast their skins several times in the course of their lives; the exuviae would be very acceptable to the collector, if they re∣tained any of the beautiful colours of the living Spiders.

To determine whether some species of Spiders could be preserved with their natural colours, I put several into spirit of wine; those with gibbous bodies soon after discharged a very considerable quantity of viscid matter, and therewith all their most beautiful colours; the smallest retained their form, and only appeared rather paler in the colours than when they were living.

During the course of last summer, among other Spiders I met with a rare species; it was of a bright yellow colour, elegantly marked with black, red, green, and purple; by some accident it was unfortunately crushed to pieces in the chip box wherein it was confined, and was therefore thrown aside as useless; a month or Page  52more after that time, having occasion to open the box, I ob∣served, that such parts of the skin as had dried against the in∣side of the box retained the original brightness of colour in a considerable degree; to further the experiment I made a similar attempt with some caution, on the body of another Spider (Aranea Diadema), and though the colours were not perfectly pre∣served, they appeared distinct.

From other observations I find, that if you kill the Spider, and immediately after extract the entrails, then inflate them by means of a blow-pipe, you may preserve them tolerably well; you must cleanse them on the inside no more than is sufficient to prevent mouldiness, lest you injure the colours, which certainly in many kinds depend on some substance that lies beneath the skin.

After inflating them, you may either inject them with fine virgin wax, or anoint the skin with oil of spike in which resin has been dissolved, and dry them in some shady place.

Of the largest kinds of foreign Spiders, the bodies are the only parts which are liable to shrivel; if they were prepared in this man∣ner their proper form would be preserved.

In 1792, Dr. Withering presented a paper to the Linnaean society, in which he relates the particulars of a new method of preserving Fungi, &c.; as we have given an account of this improvement with the instructions for the preservation of plants, we shall only observe in this place, that the composition which he has applied with so much success as a preservative of the most perishable tribes of vegetables, may hereafter prove also an excellent preservative for Spiders, and other apterous infects.