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PRACTICAL ENTOMOLOGY FOR FARMERS' SONS.
HOW TO COLLECT AND PRESERVE IXSECTS. If agricultural losses from insect depredations exceed in amount the total value of the cotton crop, or equal half the average value of the corn crop, as some entomologists affirm, it is time that young farmers should learn the names, study the anatomy, and investigate the habits, of these prolific pests of the farm, and thus acquire the means of limiting their reproduction, of accomplishing their destruction, or of “flanking” their movements as to the time and manner of their attacks. Much may be done in these directions, and more can be learned, as observers and experimenters in practical entomology increase in numbers and advance in the practical application of this branch of natural science.
How shall the boys of the farm commence such a work? First in order, the elementary principles of entomology should be studied; then the practical labor of making a working collection should be undertaken, from which incidental and valuable advantages would accrue, even if the threshold only of the science should be passed.
Many a farmer's boy might make a valuable collection of insects with half the disadvantages under which city collectors labor, if he would only manifest sufficient interest to make a beginning, if ever so small. One of our leading entomologists first became interested while working at his tailor bench, by catching wasps of different gaudy colors, and pinning them up around the walls of his shop; and others have become famous with no greater beginning. Probably the idea of entomology, or of a collection, has suggested itself to but few of the boys of the farm; as one recently wrote, when about to commence the study of entomology, “I never supposed a country boy could collect insects; only those who have time for study and travel.” It is a great mistake. A country boy has every facility; he is where he can study to the greatest advantage the insect foes with which he has to contend, where he can watch them in all their changes and transformations, and where he can not only aid materially the agriculturist, but serve the cause of science.
If farmers in this country knew more of entomology, or were better acquainted with “bugs," as many term them, such knowledge would be the means of saving thousands of dollars to productive industry and to themselves. One can hardly realize the extent of injuries done by these little depredators; but the following estimate from the American Ento. mologist of September, 1868, representing more than the total value of the cotton crop, is a startling indication of the importance of the subject: “On the whole, we are certainly speaking within bounds when we assert that, taking one year with another, this country suffers from the depredations of noxious insects to the annual amount of three hundred millions of dollars."
Regarding the writings of Dr. Fitch on the noxious insects of New York, it further states, as the opinion of prominent and enlightened agriculturists, that they had 'saved that single State fifty thousand dollars annually. If such results are reached through the efforts of one
man, what may not be accomplished with many workers in the field? As all insects are not injurious, and as many are beneficial, it is of practical value to the agriculturist to be able to discriminate between friends and foes; and this knowledge is learned only by observing the habits of the insects themselves.
A treatise on entomology is not here proposed, but simply a few practical hints on the collection and preparation of insects, hoping they may awaken an interest that will lead to progressive study of this interesting science.
Insects, as well as worms and crustaceans, (lobsters, crabs, &c.,) belong to that division of the animal kingdom known as Articulata, that is, composed of rings or segments. Insects may be distinguished by having the body divided into three distinct sections: head, thorax, and abdomen; and by having two antenna or feelers, four wings, and three pairs of legs. In flies the second pair of wings are wanting, and some few insects have none at all. This class is most commonly divided into seven groups, called orders; and these again are separated into families, tribes, genera, and species. An insect, after it is hatched from the egg, is called the larva, which when full grown casts its skin, the outer
integument hardens, and it becomes a pupa, in I
which stage it remains till it has completed its transformation, when it comes forth a perfect insect or imago.
The transformation is called complete when the changes to pupa and imago are signally marked, as shown in the accompanying figures. Bees, butterflies, &c., are examples. In grasshoppers, &c., the transformation is partial, as the insect at no period of its existence becomes inactive or ceases to take food, but grows by repeatedly casting
its skin, finally appearing in the perfect state. Fig. 1. Among insects the females differ from the males, being larger and not so brightly colored; they are often differently marked or ornamented, and generally have one less abdominal ring. The signs used to distinguish them are male and female.
Beetles are distinguished by their hard bodies, stout jaws, and thick wing. covers or elytra, which in meeting form a straight line down the back, and serve to protect the second pair, which are membranous. The larve, called grubs, generally have six true legs, and often a terminal pro-leg. In the pupa the legs and wings are free or unconfined. Transformations are complete.'
The collector in this order should be provided with a net for sweeping grass and herbage, or for beating bushes; a collecting box and several
vials of alcohol, in which to kill and preserve captures. The net is made in the same manner as the gauze net for butterflies, substituting cotton cloth for muslin. The common net may be used for this purpose, though
it is more easily torn or otherwise damaged. A water Fig. 2. net is particularly useful in collecting aquatic coleoptera. It is made of grass cloth or some coarse material, fastened to a ring a foot or more in diameter. Any box two inches deep, that can be carried in the pocket, will do for a collecting box, though for general collecting it is well to have such a one as Fig. 3, which any carpenter can mako
for a trifle. A convenient size is nine inches long, by seven wide, and two inches deep at the sides; the bottom to be made rounding, to fit the small of the back. On one end is placed a cushion for pins, and on the outside of the cover a pocket for slips of paper, &c. It should be made as light as possible, and can be carried either suspended from the shoulder, shot pouch fashion, or fastened to a belt around the waist. Delicately colored beetles, the goldsmith beetle, for example,
Fig. 3.. which is of a beautiful metallic yellow, should be left in alcohol only long enough to kill, and should then be pinned and placed in the collecting box. Sometimes, if not quite dead, a little benzine brushed on the sides of the body is necessary to quiet them.
In setting beetles the pin is inserted into the right elytron, or wingcase, so as to come out beneath, mid-way between the second and third pair of legs, otherwise the insect is liable to be damaged. It is always best to place the legs and antennæ in a natural position, so that all the joints can easily be seen. When it is desirable to show the under wings, the regular setting board may be used. Beetles that are too small to pin, flea beetles, &c., should be mounted on triangular slips, through which the pin can be thrust. They are made of bristol i board, cut first into strips a quarter of an inch in width, and then transversely, as shown by the dotted lines in Fig. 4. To these, insects are fastened either by common mucilage, or a mixture of inspissated ox gall, gum arabic and water; it should be thick enough to hold the specimen in the position in which it is placed. When there are duplicates of any species, it is well to set one or two in position to show the under side of the body.
Fig. 4. Beetles are to be met with everywhere. The tiger beetles, Cicindelidæ, inhabiting hot, sandy plains, or sunny paths, are most easily taken by allowing them to alight, and then suddenly throwing the net over them. Ground beetles, Carabidæ, are found in damp places, under sticks, stones, drift, and bark of trees; a few are found upon the leaves of trees and plants. Other families are aquatic, such as the whirligigs and divers, Dytiscidæ, Gyranidæ, and Hydrophilidae, and should be taken by means of the water net. By dredging the bottom of ponds and examining the plants, &c., brought up, many small species can be obtained. The Silphidae (burying or sexton beetles, scavengers, &c.) are found with dead animals, and sometimes on flowers. Many of the rove beetles, Staphylinida, are found in decaying animal and vegetable substances; while some of the smaller species live under bark and in ants' nests. The Lamellicornes, which are distinguished by their clubbed antennæ, [Fig. 5,] are mostly vegetable feeders, and are therefore injurious. They may be collected in summer on plants, flowers, shrubbery, &c. Copris and allies are found with excrement. The wood-boring Buprestidæ may be seen on warm summer days sunning themselves on trunks of trees Fig. 5. or on dry logs. Their allies, Elateridae, (springing or snapping beetles,) live under bark or in rotten wood. The long slender wire-worms which do so much injury in gardens produce elaters. Lightning bugs, Lampyrida, in the day-time are found upon flowers. Clerida, bright, nimble insects resembling ants, inhabit bumble-bees' nests. Granaries are infested with a beetle belonging to the Tenebrionidæ, a family resembling ground beetles, and like them found under stones, logs, bark of trees, &c.; some live in toad-stools. Blister flies are soft-bodied insects, found on potato tops, flowers of golden rod, &c. The Curculionidae, snout beetles, or weevils, infest grain, seeds, or fruits, and many species live in wood, under bark, or in plants and flowers. The Longicornes, in the larval state, are wood borers. These beetles, which are among the largest of the order, can be collected in great numbers in spring, around saw-mills, lumber yards, wood-piles, and in forests; many species frequent flowers in summer. Flea beetles, Chrysomelidæ, live in all their stages upon the leaves of plants. The Coccinellidæ, (lady-birds,) which are nearly all beneficial, are useful in destroying plant lice.
Cockroaches, crickets, grasshoppers, &c., are provided with jaws; the upper wings are thick and opaque, while the large under ones are netveined, and fold like a fan. The transformations are partial, the larvæ and pupæ resembling the perfect insect, but wanting wings.
Orthoptera when collected can be thrown into alcohol, and there allowed to remain until it is convenient to set them, though a better way is to kill them with benzine or ether, and place immediately in the collect. ing box. To save trouble of pinping in the field, grasshoppers may be put in a little box, each insect wrapped in a piece of soit paper two or three inches square, to prevent injury, first treating it to a generous dose of benzine, which for convenience should be carried in a small vial having a bruslí fastened inside to the cork. Grasshoppers very soon lose their color when placed in alcohol; the delicate under wings, which in many species are bright colored, become brown and soiled. If treated with benzine, and immediately pinned and placed in the collecting box, they are also liable to injury by " coming to life and kicking their legs off, as collectors are accustomed to say. “They should be pinned through a little triangular spot between the bases of the fore wings. They are also often pinned through the prothorax, or through the right elytron, as in coleoptera.” It is well to set several individuals of a species with the wings spread as in flight; some collectors prefer the wings set only on one side, leaving the other side to show the insect at rest.
The insects belonging to this order are nearly all injurious to vegetation. Cockroaches feed upon a variety of substances in houses, &c., and the Nantes or “rear-horses" prey upon other insects. Earwigs, Forficulida, are nocturnal insects, found hiding by day in the leaves of flowers; they may be taken with the net just before sunset, when they are most active. Many cockroaches, Blattarida, are found under stones, sticks, bark of decaying trees, and in damp situations. The field species are smaller than those commonly found in houses. The walking sticks, Phasmida, live upon the tender leaves and shoots of shrubbery and trees, and very much resemble dry twigs. Crickets, Gryllides, are found during the greater part of the year under logs, stones, and in sheltered places, such as old stone walls. The mole cricket, Gryllotalpa, burrows in subterranean galleries which it forms in meadows and swamp lands. Katydids represent a family of broad-winged grasshoppers, the Locustaria, nearly all of which are green in color. They are found on the leaves of trees and shrubbery early in autumn, and may be collected by beating Grasshoppers, Acrydii, are common everywhere during the summer months and until late in the fall. They are found most numerous in meadows and fields, on heaths and barren rocky hills, and a few are found upon bare sandy places, near streams. As many are swift of flight, the net should be used in their capture.
NEUROPTEKA. Drutjük jiics, lacc-wing flies, Jay-flies, white ants, dc., are insects with jaws, having four broad net-veined wings, the second pair generally being the largest. The transformations are incomplete, larvæ and pupa active. The species are nearly all aquatic.
The insects of this order are very predatory, and are consequently beneficial, living upon other insects in the larval and perfect stage of their existence. The habits of aquatic larvæ may be watched in the aquarium, though the more powerful should be kept from the weaker ones. In this way, with care, many additions can be made to the cabinet, altogether forming an interesting as well as a profitable study.
During the warm weather white ants are found in great numbers in rotten wood, or in rails and fence posts, and under stones. As they are very delicate, they should be pinned at once. Caddice flies, Phrygancidæ, in the larval state inhabit cylindrical cases made of sticks, sand, &c., living in the water, and feeding upon plants and small aquatic insects. The perfect insects are usually found flying near the pools in which they have passed their first stages, and should be pinned as soon as taken in the net. The larvæ of ant-lions live in cone-shaped pits in the sand, near which situations the perfect insects may be found. They are also found flying near woods. Lace-winged flies are found upon plants and shrubbery; and, as they are attracted to light, sometimes in the evening fly into houses. The Libellulidæ, “Devil's darning needles," dragon flies, &c., may be seen in warm summer days flying around pools of water, hawking for other insects. As their rapid flight makes them difficult to capture, they are most easily taken by throwing the net over them when settled. Dragon flies should be caught with the net and killed by brushing with benzine, the larger kinds placed in triangular slips of paper or old envelope corners, while the more delicate species should be pinned and put in the collecting box. They are most numerons near pools and marshes, and in damp places generally, and are attracted to fire or bright light at night. Agrionidæ are tho small, delicate, brilliantly colored species seen hovering over plants near brooks, ditches, or in meadows, suspending themselves, apparently motionless, then suddenly alighting; they should be pinned in the colleeting box as soon as taken. Ephemerce, or May-flies, are most numerous in the evening. Thysanura is a wingless species, found in manure heaps, among fallen leaves, under sticks, stones, bark of trees, and in damp places. Lepisma, also wingless, is found in old books, in which it hides during the day.
IIYMENOPTERA. Bees, wasps, ants, Lc., are hard-bodied insects, with four narrow membranous wings, of which the hinder ones are the smaller, and a hard ovipositor or sting at the extremity of the body. The transformations are complete. The larvæ are footless grubs, though a few resemble caterpillars. Pupæ have true wings and legs free.
In collecting hymenoptera the student should be provided with the usual net and collecting box, two or three wide-mouthed bottles of alcohol, and boxes of different sizes for nests. After capturing an insect it should be stupefied with benzine, then pinned and placed in the collecting box, or thrown into alcohol. Nests should be searched for, that their young may be reared and their habits studiously observed, especially the saw-flies, gall-flies, &c. They may be found adhering to