INSECTS, INSECTA, in natural history, a smaller sort of animals, commonly supposed to be exsanguious; and distinguished by certain incisures, cuttings, or indentations in their bodies. The word is originally Latin, formed of in, and seco, "I cut;" the reason of which is, that in some of this tribe, as ants, the body seems to be cut or divided into two; or because the bodies of many, as worms, caterpillars, &c. are composed of divers circles, or rings, which are a sort of incisures.
By some natural historians, this class of animals is considered as the most imperfect of any, while others prefer them to the larger animals. One mark of their imperfection is said to be, that many of them can live a long time, though deprived of those organs which are necessary to life in the higher ranks of nature. Many of them are furnished with lungs and an heart, like the nobler animals; yet the caterpillar continues to live, though its heart and lungs, which is often the case, are entirely eaten away.—It is not, however, from their conformation alone that insects are inferior to other animals, but from their instincts also. It is true, that the ant and the bee present us with striking instances of assiduity; yet even these are inferior to the marks of sagacity displayed by the larger animals. A bee taken from the swarm is totally helpless and inactive, incapable of giving the smallest variation to its instincts. It has but one single method of operating; and if put from that, it can turn to no other. In the pursuits of the bumble, there is something like choice; but in the labours of the bee, the whole appears like necessity and compulsion.—All other animals are capable of some degree of education; their instincts may be suppressed or altered; the dog may be taught to fetch and carry, the bird to whistle a tune, and the serpent to dance: but the insect has only one invariable method of operating; no arts can turn it from its instincts; and indeed its life
life is too short for instruction, as a single season often terminates its existence.—Their amazing number is also an imperfection. It is a rule that obtains through all nature, that the nobler animals are slowly produced, and that nature acts with a kind of dignified economy; but the meaner births are lavished in profusion, and thousands are brought forth merely to supply the necessities of the more favourite part of the creation. Of all productions in nature, insects are by far the most numerous. The vegetables which cover the surface of the earth bear no proportion to the multitudes of insects; and though, at first sight, herbs of the field seem to be the parts of organized nature produced in the greatest abundance, yet, upon more minute inspection, we find every plant supporting a mixture of scarce perceptible creatures, that fill up the compass of youth, vigour, and age, in the space of a few days existence.—In Lapland, and some parts of America, the insects are so numerous, that if a candle is lighted they swarm about it in such multitudes, that it is instantly extinguished by them; and in these parts of the world, the miserable inhabitants are forced to smear their bodies and faces with tar, or some other unctuous composition, to protect them from the stings of their minute enemies.
On the other hand, Swammerdam argues for the perfection of insects in the following manner. "After an attentive examination (says he) of the nature and anatomy of the smallest as well as the largest animals, I cannot help allowing the least an equal, or perhaps a superior, degree of dignity. If, while we dissect with care the larger animals, we are filled with wonder at the elegant disposition of their parts, to what an height is our astonishment raised, when we discover all these parts arranged, in the least, in the same regular manner! Notwithstanding the smallness of ants, nothing hinders our preferring them to the largest animals, if we consider either their unwearied diligence, their wonderful strength, or their inimitable propensity to labour. Their amazing love to their young is still more unparalleled among the larger classes. They not only daily carry them to such places as may afford them food; but if by accident they are killed, and even cut into pieces, they will with the utmost tenderness carry them away piecemeal in their arms. Who can shew such an example among the larger animals which are dignified with the title of perfect? Who can find an instance in any other creature that can come in competition with this?"
On this dispute it is only necessary to observe, that the wisdom of the Creator is so conspicuous in all his works, and such surprising art is discovered in the mechanism of the body of every creature, that it is very difficult, if not impossible, to say where it is most, and where it is least, to be observed.—The nature and properties of insects are certainly very wonderful. Many particulars relating to them may be found under different articles of this work; but those who desire to see this subject treated in a full and ample manner, must have recourse to the works of Reaumur and Swammerdam.
Of the Kinds of Insects, and where the Collector for the Cabinet may find them. Insects in general are known to most people, the systematic distinctions but too few; nor have we any English names for the greatest
part of them. The general denominations of beetles, butterflies, moths, flies, bees, wasps, and a few other common names, are all that our language supplies. It would, therefore, be in vain to enumerate the immense variety of genera and species to any person unskilled in the science of entomology: we may, however, give directions under general names where to find each kind.
The class of insects is divided by Linnæus into seven orders. See ZOOLOGY.
I. The COLEOPTERA, (from coleos, a sheath, and pteron, a wing,) are such insects as have crustaceous elytra or shells, which shut together, and form a longitudinal future down the back of the insect; as the beetle, (buprestis ignita), fig. 11. Many of them (as the scarabaeus or chafer, dermestes or leather-eater, bister or mimic-beetle, staphylinus or rove-beetle, &c.) are found in and under the dung of animals, especially of cows, horses, and sheep. Some (as lucanus or flag-beetle, cerambyx or capricorn beetle, dermestes, &c.) are found in rotten and half-decayed wood, and under the decayed bark of trees. Others (as bister, silpha or carrion-beetle, staphylinus, &c.) on the carcasses of
animals that have been dead four or five days; on moist bones that have been gnawed by dogs or other animals; on flowers having a fetid smell; and on several kinds of fungous substances, particularly the rotten and most stinking. Others (as byrrhus, curculio or weevil, bruchus or seed-beetle, &c.) may be found in a morning about the bottoms of perpendicular rocks and sand-banks, and also upon the flowers of trees and herbaceous plants. Many kinds (as gyrinus or whirl-beetle, dytiscus or water-beetle, &c.) may be caught in rivers, lakes, and standing pools, by means of a thread-net, with small meshes, on a round wire-hoop, fixed at the end of a long pole. In the middle of the day, when the sun shines hot, some (as the coccinella or lady-fly, buprestis or burn-cow, chrysomela or golden honey-beetle, cantharis or soft-winged-beetle, elater or spring-beetle, neodyalis or elipt-winged beetle, &c.) are to be seen on plants and flowers, blighted trees and shrubs. Others (as lampyris or glow-worm, &c.) frequent moist meadows, and are best discovered at night, by the shining light which they emit. A great variety sit close on the leaves of plants, particularly of the burdock, elecampane, coltsfoot, dock, thistle, and the like, (as the casida or tortoise-beetle, &c.); or feed on different kinds of tender herbs (as the meloe or blister-beetle.) Numbers (as the tenebrio or stinking-beetle,) may be found in houses, dark cellars, damp pits, caves, and subterraneous passages; or on umbelliferous flowers, (as the cerambyx, pinus, &c.); or on the trunks as well as on the leaves of trees, in timber-yards, and in the holes of decayed wood. Some (as the leptura or wood-beetle, cicindela or glossy-beetle, &c.) inhabit wild commons, the margins of pools, marshes, and rivulets; and are likewise seen creeping on flags, reeds, and all kinds of water-plants. Multitudes (as the carabus or ground-beetle) live under stones, moss, rubbish, and wrecks near the shores of lakes and rivers. These are found also in bogs, marshes, moist places, pits, holes of the earth, and on stems of trees; and in an evening they crawl plentifully along path-ways after a shower of rain. Some (as the forficula or earwig) may be discovered
Insects. in the hollow stems of decayed umbelliferous plants, and on many sorts of flowers and fruits.
II. HEMIPTERA, (from hemis, half, and pteron, a wing,) have their upper wings usually half crustaceous and half membranaceous, not divided by a longitudinal suture, but incumbent on each other; as the cimex, fig. 12. Some of these (as the blatta or cockroach) are found about bake-houses, &c.; others (as the mantis or camel-cricket, gryllus or locust, fulgora, cicada, or flea-locust, cimex or bug, &c.) on grass, and all kinds of field-herbage. Some (as notonecta or boat-fly, nepa or water-scorpion, &c.) frequent rivers, lakes, and standing pools.
III. LEPIDOPTERA, (from lepis, a scale, and pteron, a wing,) are insects having four wings, covered with fine scales in the form of powder or meal; as in the butterfly, (papilio antiopa,) fig. 13. In the day, when the sun is warm, butterflies are seen on many sorts of trees, shrubs, plants, and flowers. Moths may be seen in the day-time, fitting on pales, walls, trunks of trees, in shades, out-houses, dry holes, and crevices; on fine evenings, they fly about the places they inhabit in the day-time: some (as the sphinx or hawk-moth,) are seen flying in the day-time over the flowers of honey-suckles and other plants with tubular flowers. Insects of this species seldom fit to feed, but continue vibrating on the wing, while they thrust the tongue or proboscis into the flowers.
IV. NEUROPTERA, (from neuron, a nerve, and pteron, a wing,) have four membranous transparent naked wings, generally like network; as in the panorpa coa, fig. 14. Of these, some (as the myrmecoleon, hemerobius or pearl-fly, rapidia or camel-fly, &c.) are found in woods, hedges, meadows, sand-banks, walls, pales, fruits, and umbelliferous flowers. Others (as libellula or dragon-fly, ephemera or may-fly, phryganea or spring-fly, &c.) fly about lakes and rivers in the day.
V. HYMENOPTERA, (from hymen, a membrane, and pteron, a wing,) are insects with four membranous wings, tail furnished with a sting; as in the tenthredo, fig. 15. These, including wasps, bees, &c. frequent hedges, shrubs, flowers, and fruits.
VI. DIPTERA, (from duo, two, and pteron, a wing,) are such as have only two wings, and poisons; as in the fly, fig. 16. Flies of various kinds constitute this class; of which some (as estras or gad-fly, musca or fly, tubanus or whame,) fly about the tops of trees, little hills, horses, cows, sheep, ditches, dunghills, and every offensive object. Others (as tipula, conops, asilus or wasp-fly, &c.) are found on all sorts of flowers, particularly those of a fetid smell.
VII. APTERA, (from a, without, and pteron, a wing,) insects having no wings. This last division contains scorpions, spiders, crabs, lobsters, &c.
Of Catching and Preserving Insects for Collections. In the following directions, we shall relate the methods of killing them the most readily, and with the least pain, as the pursuit of this part of natural history hath been often branded with cruelty; and however reasonably the naturalist may exculpate himself by pleading the propriety of submitting to an evil which leads to useful discoveries, yet for wanton cruelty there never can be a just pretext:
—The poor beetle that we tread upon,
In corp'ral sufferance feels a pang as great
As when a giant dies.
1. The first class, consisting of beetles (coleoptera), are hard-winged. Many kinds fly about in the day, others in the evening, some at night only. They may be caught with a gauze-net, or a pair of forceps covered with gauze. When they are taken, stick a pin thro' the middle of one of the hard wings, and pass it thro' the body. They may be killed instantly, by immersion in hot water, as well as in spirit of wine; then stick them on a piece of cork, and afterwards carefully place their legs in a creeping position, and let them continue exposed to the air until all the moisture is evaporated from their bodies. Beetles may also be preserved in spirit of wine, brandy, or rum, closely corked up.
2. Insects of the second class (hemiptera) may be killed in the same manner as beetles, and likewise by means of a drop of the ethereal oil of turpentine applied to the head; or in the manner to be described under the next class for killing moths.
3. The division of butterflies and moths, (lepidoptera), as well as all flies within membranaceous wings, should be caught with a gauze net, or a pair of gauze forceps: when taken in the forceps, run a pin through the thorax or shoulders, between the forewings. After this is done, take the pin by the head, and remove the forceps, and with the other hand pinch the breast of the insect, and it will immediately die: the wings of butterflies should be expanded, and kept so by the pressure of small slips of paper for a day or two. Moths expand their wings when at rest, and they will naturally take that position.
The larger kinds of these insects will not so readily expire by this method, as by sticking them upon the bottom of a cork exactly fitted to the mouth of a bottle, into which a little sulphur had been put, and by gradually heating the bottle, till an exhalation of the sulphur take place, when the insect instantly dies, without injuring its colours or plumage.
The best method of having the most perfect butterflies, is to find out, if possible, the larva or caterpillar of each, by examining the plants, shrubs, or trees, they usually feed upon, or by beating the shrubs and trees with long poles, and thereby shaking the caterpillars into a sheet spread underneath to receive them; to put them into boxes covered with thin canvas, gauze, or cat-gut, and to feed them with the fresh leaves of the tree or herb on which they are found; when they are full grown, they will go into the pupa or chrysalis state, and require then no other care till they come out perfect butterflies, at which time they may be killed, as before directed. Sometimes these insects may be found hanging to walls, pales, and branches of trees, in the chrysalis state.
Moths might likewise be procured more perfect, by collecting the caterpillars, and breeding them in the same manner as butterflies. As the larvae or caterpillars cannot be preserved dry, nor very well kept in spirit, it would be satisfactory if exact drawings could be made of them while they are alive and perfect. It may be necessary to observe, that in breeding these kinds of insects, some earth should be put into the boxes, as likewise some rotten wood in the corners; because, when the caterpillars change into the pupa
or chrysalis state, some go into the earth, and continue under ground for many months before they come out into the moth state; and some cover themselves with a hard shell, made up of small pieces of rotten wood.
4. The fourth class of insects (neuroptera) may be killed with spirit of wine, oil of turpentine, or by the fumes of sulphur.
5. Those of the next class (hymenoptera) may be killed in the same manner. A pin may be run thro' one of their wing-shells and body.
6. Insects of the sixth class (diptera) may likewise be killed by spirit, or by fumes of sulphur.
7. Those of the last division (aptera) are in general subjects which should be kept in spirit.
When in search of insects, we should have a box suitable to carry in the pocket, lined with cork at the bottom and top to flick them upon, until they are brought home. If this box be strongly impregnated with camphor, the insects soon become stupified, and are thereby prevented from fluttering and injuring their plumage. Besides a gauze forceps, the collector should have a large musquito gauze-net, and also a pin-cushion with three or four different sizes of pins, to suit the different sizes of insects.
In hot climates, insects of every kind, but particularly the larger, are liable to be eaten by ants and other small insects; especially before they are perfectly dry: to avoid this, the piece of cork on which our insects are stuck in order to be dried, should be suspended from the ceiling of a room, by means of a slender string or thread; besmear this thread with bird-lime, or some adhesive substance, to intercept the rapacious vermin of these climes in their passage along the thread.
After our insects are properly dried, they may be placed in the cabinet or boxes where they are to remain: these boxes should be kept dry; and also made to shut very close, to prevent small insects from destroying them; the bottoms of the boxes should be covered with pitch, or green wax, over which paper may be laid; or, which is better, lined with cork, well impregnated with a solution of corrosive sublimate mercury in a saturated solution of crude sal-ammoniac in water, an ounce of which will dissolve 20 scruples of the sublimate.
The finest collections have been ruined by small insects, and it is impossible to have our cabinets too secure. Such insects as are thus attacked may be fumigated with sulphur, in the manner described for killing moths; if this prove ineffectual, they may be immersed in spirit of wine, without much injuring their fine plumage or colours, and afterwards let them be sprinkled about their bodies and infertions of the wings with the solution above-mentioned. But baking the insects in an oven, in the manner described for Birds (under that article), is the most effectual method of extirpating these enemies; however, the utmost caution is requisite in this process, in regulating the heat of the oven.
N. B. All kinds of insects having no wings, may be preserved in spirits, brandy, or rum; except crabs, lobsters, and the like, which may conveniently be preserved dry.
Insects giving root to Plants. Of this we have an account, by Mr Fourgeroux, in the Memoirs of the A-
cademy of Sciences for 1769. The plants, of which Mr Fourgeroux gives an account, are perfectly the reverse of the worm-plant of China, described by Mr Reaumur in the year 1726. For, in that case, a worm fixes its snout into the extremity of the plant, and derives nourishment from it. But the plants, of which an account is here given, derive their nourishment from the animals.
The greatest part of the animal-plants which he has seen, grow, he tells us, on the chrysalis of a species of cicada. The plant growing on these insects has got the generic name of clavaria, because its stalks and branches, when it has any, are terminated by tubercles, which give the appearance of little clubs. The root of this plant, in general, covers the body of the insect, and sometimes is even extended over its head. When these productions have for some time been preserved in spirits, the plant and animal may be separated from each other without hurting either. Small grooves, formed by the rings of the animal, may be observed running cross the roots of the plant: but no vestige can be found of the root's having any where penetrated the body of the insect. These plants produce fibres differing in length and number. The fibres are terminated by tubercles, which, before the plant arrives at maturity, are solid; but, after that period, they are found punctured, probably by worms which have suffered a metamorphosis upon escaping from them.
According to Mr Fourgeroux, plants grow, not only on the chrysalis of the cicada, but upon the cicada itself. He saw one of this kind upon a cicada brought from Cayenne. The plant, in this case, differed from the clavaria already mentioned. It was a species of fucus, composed of long, white, silky fibres, covering the body of the insect, and extending from seven to eight lines above and below its belly.
The author has found the clavaria growing upon worms. He has found it chiefly upon worms, which suffering a metamorphosis, become afterwards a small species of May-bug. This chrysalis, he observes, is very different from that of the cicada; and, even in its worm-state, may easily be distinguished from it.
After describing these different species of animal-plants, the author next proceeds to offer his opinion upon this subject. He first considers what had been said by Dr Watson, in the Philosophical Transactions, concerning the vegetating-fly of the Caribbee islands*. Dr Watson's account of these flies is, that they bury themselves about the month of May, and begin to be metamorphosed in June; and that the little plant which grows upon them resembles a branch of coral, is about three inches in height, and carries small protuberances, where worms are generated, which are again converted into flies. The author imagines, that, in this account, Dr Watson has been deceived by the worms, which he has already observed will eat into the clavaria, and undergo a change in the holes which they have there made. Mr Fourgeroux is rather inclined to adopt the opinion of Dr Hill, founded upon observations made at Martinico. There the cicadæ are very frequent; and, during their chrysalis state, bury themselves among dead leaves, to wait their metamorphosis. Dr Hill imagines, that the seeds of the clavaria are then attached to them, and are afterwards developed, much in the same manner as the fungus ex pedo equino
Insects equino grows upon the hoofs of dead horses. ||
Inspiration. It may appear astonishing, that the clavaria should attach itself so constantly to the nymphæ of the cicadæ in America, as it is not observed to do so in other countries. For this Mr Fourgeroux attempts to account, from viewing the clavaria as a parasite peculiar to this species of insect; from the great number of the nymphæ of cicadæ which abound in America; and from the circumstances of the climate and soil, which may render this phenomenon very common there, although it be not observed in Europe.
Insects blown from the Nose. Of this we are furnished with many accounts in the works of medical authors. The fact is confirmed by Dr Monro *, who has received at different times some of these insects from different persons. They were all of the scelopendra kind, though not exactly answering to any description of Linnæus. One of these he received from Mr Hill surgeon in Dumfries. It was an inch and a half long; and lived some hours after it was discharged, creeping about slowly on a table. It was then put into ardent spirits, soon after which it died.