Essays on the Microscope / Containing a Practical Description of the Most Improved Microscopes, a General History of Insects, etc., etc.

by George Adams

The collector being now furnished with the necessary instruments, it will be proper to give him such instructions as may enable him to use them. With regard to the manner of using the net with expertness and success, this knowledge will be much better acquired by practice than by the most ample description. Harris, in his elegant work, The Aurelian, has been rather diffusive than clear on this subject. Having caught the butterfly or moth in the net, it will be necessary to proceed with caution, as on killing it properly its beauty in a great measure depends. It should not be laid hold of indiscriminately in any part; but by managing skilfully the net, its wings must, if possible, be brought into an erect position or close together; then press the under part of the thorax or breast between the thumb and the fore-finger sufficiently hard to kill the insect. By carefully attending to these directions, the wings will not be distorted or the plumage injured.

The net being now opened, the insect is to be laid hold of by one of its antennæ or horns, and again placed between the thumb and fore-finger; in which situation it is to be held, while a pin proportioned to its size is stuck through the upper part of the thorax or back; it may then be affixed to the pocket-box by sticking the point of the pin into the cork lining. The larger kinds of these insects, especially moths and hawk-moths, which are far more tenacious of life than butterflies, will not expire so readily by this method, as by fixing them upon the bottom of a cork exactly fitted to the mouth of a bottle into which a little sulphur has been put; by gradually heating the bottle till an exhalation of the sulphur takes place, the insect usually dies without injuring its colour or plumage.

THE METHOD OF MANAGING THEM IN THEIR FLY STATE.

Though by the means just described these insects may be caught uninjured, some farther care is requisite in order to make them appear to advantage; this is called setting them, and is performed in the following manner. The insect being stuck through with a pin of a proper size, is to be placed before its wings are become stiff, on a piece of cork, having a smooth surface and covered with white paper. The body of the fly should not be made to touch the cork when the insect is affixed to it, but to stand up some little distance from it, as only the edges of both wings are intended to touch, not the wings to lie flat on the cork. The wings are then to be expanded, as in the [figure], with a fine needle, or some sharp-pointed instrument. The instruments used in the operation for the eye called couching, being fixed to taper handles, are peculiarly commodious for this purpose.

The upper edges of the superior wings are to be placed in a line with the head of the insect, and they are to be kept in this situation by means of little braces, formed of card-paper and cut in the shape represented in the figure; a number of which should always be kept in readiness in a small box. These must be proportioned to the size of the wings, and fitted to their shape, by being more or less bent; by a proper attention to which, the spots, &c. on both wings are rendered conspicuous, and the beauties of the insect exhibited in full perfection. To acquire the method, however, of setting them well, requires considerable practice and some ingenuity. After remaining in this position four or five days, or till the insect is become thoroughly stiff, the braces may be taken off, and the insect removed into the store box. The shape of the store box is immaterial; it should, however, be flat, and may be made either of wood, or, which is preferable, of tin. The inside should be lined with thin cork and covered with paper, and some slips of cloth glued to its edges to make it shut closer, and thus exclude as much as possible insects and animalcula; a little camphor tied in a bit of rag, and pinned to a corner of the box, will be found very useful to prevent their depredations.

It is particularly to be observed, that there is a continual succession of insects as well as of plants; some appear with the early primrose, others accompany the late-flowering ivy: so that in this respect, the aurelian and entomologist may regulate their excursions by those of the botanist; the latter would in vain search for the ranunculus ficaria or pile-wort, in the month of July, and the former be equally disappointed in seeking for the papilio cardamines, orange-tip, in the month of August.

Some of these insects continue longer in their fly state, and their plumage is less injured by flying, than others; some continue for a few days only; others, several weeks. In general, moths and butterflies, unless they are caught the first day of their coming out of chrysalis, are of small value; hence arises the necessity of carefully watching those particulars, and of making frequent excursions in order to obtain them in the greatest perfection.

Butterflies are to be caught on the wing only when the sun shines warm. They inhabit a variety of places; the greatest number of them frequent woods, and may be taken in or near them, as the papilio iris, purple emperor; papilio hyperantus, ringlet; and most, if not all the fritillaries. Some delight in meadows, as the papilio jurtina, meadow brown; galathea, marbled white; C. album, comma; rhamni, brimstone: and others frequent gardens, as the brassicæ and rapæ, large and small garden white; others, again, clover fields, corn fields, heaths, lanes, &c. Many of those which frequent woods are taken with much greater facility in the morning, a few hours after sun-rise; at which time they are found feeding on the flowers that grow by the sides of the woods; afterwards, when the sun shines with greater strength, they fly high, and with such rapidity, as not to be taken but with the utmost difficulty.

Moths fly chiefly in the evening, a little after sun-set. Like butterflies, they inhabit a variety of places, and are to be met with in the greatest plenty near woods; they may also be taken in great numbers in the day-time by beating the hedges, &c. more particularly in the afternoon, as the least motion will then put them on the wing. They are likewise frequently met with in the day-time sticking to the bark of trees, on walls, and pales that surround gardens, &c. and may be thus caught in great perfection. Some few, like the butterflies, fly in the middle of the day, when the sun shines warm, over the flowers of honey-suckles, and other plants with tubular flowers. Insects of this species seldom sit to feed, but continue vibrating on the wing while they thrust their tongue or proboscis into the flower.