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probably too great for our country, where vast tracts are covered with forests, and the other original vegetable races still hold possession of the soil. There are above 1200 flowering plants in Massachusetts, and it will be within bounds to estimate the species of insects at 4800, or in the proportion of four to one plant. To facilitate the study of such an immense number, some kind of classification is necessary; it will be useful to adopt one, even in describing the few species now before us. The basis of this classification is founded upon the structure of the mouth, in the adult state, the number and nature of the wings, and the transformations. The first great divisions are called orders, of which the following seven are very generally adopted by naturalists.

1.- COLEOPTERA (Beetles). Insects with jaws, two thick wing-covers meeting in a straight line on the top of the back, and two filmy wings, which are folded transversely. Transformation complete. Larvæ, called grubs, generally provided with six true legs, and sometimes also with a terminal prop-leg; more rarely without legs. Pupa with the wings and the legs distinct and unconfined.

Many of these insects, particularly in the larva state, are very injurious to vegetation. The tiger-beetles (Cicindelade*), the predaceous ground-beetles (Carabida), the diving-beetles (Dytiscide), the lady-birds (Coccinellade), and some others, are eminently serviceable by preying upon caterpillars, plant-lice, and other noxious or destructive insects. The water-lovers (Hydrophilida), rove-beetles (Staphylinida), carrionbeetles (Silphada), skin-beetles (Dermestada, Byrrhide, and Trogida), bone-beetles (some of the Nitidulada and Clerida), and various kinds of dung-beetles (Sphæridiada, Histeride, Geotrupidat, Coprididat, and Aphodiadæt), and clocks (Pimeliade and Blaptida), act the useful part of scavengers, by removing carrion, dung, and other filth, upon which alone they and their larvæ subsist. Many Coleoptera (some Staphylinida and Nitidulada, Diaperidide, some Serropalpida, Myce

• See the Catalogue of Insects appended to Professor Hitchcock's Report on the Geology, Mineralogy, Botany, and Zoölogy of Massachusetts. 2d edit. 8vo. Amherst. 1835.

† All the Scarabæidæ of my Catalogue, from Ateuchus to Geotrupes inclusive, to which may be added many included in the genus Scarabeus.

tophagida, Erotylida, and Endomychide) live altogether on agarics, mushrooms, and toadstools, plants of very little use to man, many of them poisonous, and in a state of decay often offensive; these funguseaters are therefore to be reckoned among our friends. There are others, such as the stag-beetles (Lucanida), some spring-beetles (Elaterida), darkling-beetles (Tenebrionida), and many bark-beetles (Helopida, Cistelada, Serropalpide, Edemerade, Cucujada, and some Trogositada), which, living under the bark and in the trunks and roots of old trees, though they may occasionally prove injurious, must, on the whole, be considered as serviceable, by contributing to destroy, and reduce to dust, plants that have passed their prime and are fast going to decay. And, lastly, the blistering-beetles (Cantharidide) have, for a long time, been employed with great benefit in the healing art.

2.- ORTHOPTERA (Cockroaches, Crickets, Grasshoppers, &c.). Insects with jaws, two rather thick and opake upper wings, overlapping a little on the back, and two larger, thin wings, which are folded in plaits, like a fan. Transformation partial. Larvæ and pupæ active, but wanting wings.

All of the insects of this order, except the camel-crickets (Mantida), which prey on other insects, are injurious to our household possessions, or destructive to vegetation.

3.- HEMIPTERA (Bugs, Locusts, Plant-lice, d.c.). Insects with a horny beak for suction, four wings, whereof the uppermost are generally thick at the base, with thinner extremities, which lie flat, and cross each other on the top of the back, or are of uniform thickness throughout, and slope at the sides like a roof. Transformation partial. Larvæ and pupæ nearly like the adult insect, but wanting wings.

The various kinds of field and house bugs give out a strong and disagreeable smell. Many of them (some Pentatomade and Lygaida, Cimicida, Reduviada, Hydrometrada, Nepada, and Notonectada,) live entirely on the juices of animals, and by this means destroy great numbers of noxious insects ; some are of much service in the arts, affording us the costly cochineal, scarlet grain, lac, and manna ; but the benefits derived from these are more than counterbalanced by the injuries committed by the domestic kinds, and by the numerous tribes of plant-bugs, locusts or cicada, tree-hoppers, plant-lice, bark-lice, mealy bugs, and the like, that suck the juices of plants, and require the greatest care and watchfulness on our part to keep them in check.

4.— NEUROPTERA (Dragon-flies, Lace-winged flies; May-flies, Ant-lion, Day-fly, White ants, foc.). Insects with jaws, four netted wings, of which the hinder ones are the largest, and no sting or piercer. Transformation complete, or partial. Larva and pupa various.

The white ants, wood-lice, and wood-ticks (Termitida and Psocida), the latter including also the little ominous death-watch, are almost the only noxious insects in the order, and even these do not injure living plants. The dragon-fies, or, as they are commonly called in this country, devil's needles (Libellulada), prey upon gnats and mosquitos; and their larvæ and pupæ, as well as those of the day-flies (Ephemerade), semblians (Semblidida), and those of some of the May-flies, called cadis-worms (Phryganeade), all of which live in the water, devour aquatic insects. The predaceous habits of the ant-lions (Myrmeleontida) have been often described. The lace-winged flies (Hemerobiada), in the larva state, live wholly on plant-lice, great numbers of which they destroy. The mantispians (Mantispade), and the scorpion-flies (Panorpada), are also predaceous insects.

5. – LEPIDOPTERA (Butterflies and Moths). Mouth with a spiral sucking-tube; wings four, covered with branny scales. Transformation complete. The larvæ are caterpillars, and have six true legs, and from four to ten fleshy prop-legs. Pupa with the cases of the wings and of the legs indistinct, and soldered to the breast.

Some kinds of caterpillars are domestic pests, and devour cloth, wool, furs, feathers, wax, lard, four, and the like; but by far the greatest number live wholly on vegetable food, certain kinds being exclusively leaf-eaters, while others attack the buds, fruit, seeds, bark, pith, stems, and roots of plants.

6.- HYMENOPTERA (Saw-flies, Ants, Wasps, Bees, &-c.). Insects with jaws, four veined wings, in most species, the hinder pair being the smallest, and a piercer or sting at the extremity of the abdomen. Transformation complete. Larvæ mostly maggot-like, or slug-like; of some, caterpillar-like. Pupæ with the legs and wings unconfined.

In the adult state these insects live chiefly on the honey and pollen of flowers, and the juices of fruits. The larvæ of the saw-flies (Tenthredinida), under the form of false-caterpillars and slugs, are leaf-eaters, and are oftentimes productive of much injury to plants. The larvæ of the xiphydrians (Xiphydriada), and of the horn-tails (Urocerida), are borers and wood-eaters, and consequently injurious to the plants inhabited by them. Pines and firs suffer most from their attacks. Some of the warty excrescences on the leaves and stems of plants, such as oak. apples, gall-nuts, and the like, arise from the punctures of four-winged gall-fies (Diplolepidide), and the irritation produced by their larvæ, which reside in these swellings. The injury caused by them is, com. paratively, of very little importance, while, on the other hand, we are greatly indebted to these insects for the gall-nuts that are extensively used in coloring, and in medicine, and form the chief ingredient in ink. We may, therefore, write down these insects among the benefactors of the human race. Immense numbers of caterpillars and other noxious insects are preyed upon by internal enemies, the larvæ of the ichneumonflies (Evaniade, Ichneumonida, and Chalcidida), which live upon the fat of their victims, and finally destroy them. Some of these ichneumonflies (Ichneumones ovulorum*) are extremely small, and confine their attacks to the eggs of other insects, which they puncture, and the little creatures produced from the latter find a sufficient quantity of food to supply all their wants within the larger eggs they occupy. The ruby. tails (Chrysidida), and the cuckoo-bees (Hylaus, Sphecodes, Nomada, Melecta, Epeolus, Cæliorys, and Stelis), lay their eggs in the provisioned nests of other insects, whose young are robbed of their food by the earlier hatched intruders, and are consequently starved to death. The wood-wasps (Crabronida), and numerous kinds of sand-wasps (Larrada, Bembicida, Sphegida, Pompilida, and Scoliada), mud-wasps (Pelo. paus), the stinging velvet-ants (Mutillada), and the solitary wasps (Odynerus and Eumenes), are predaceous in their habits, and provision their nests with other insects, which serve for food to their young. The food of ants consists of animal and vegetable juices; and though these industrious little animals sometimes prove troublesome by their fondness for sweets, yet, as they seize and destroy many insects also, their occasional trespasses may well be forgiven. Even the proverbially irritable paper-making wasps and hornets (Polistes and Vespa), are not without their use in the economy of nature ; for they feed their tender offspring not only with vegetable juices, but with the softer parts of other insects, great numbers of which they seize and destroy for this purpose. The solitary and social bees (Andrenada and Apida) live wholly on the honey and pollen of flowers, and feed their young with a mixture of the same, called bee-bread. Various kinds of bees are domesticated for the sake of their stores of wax and honey, and are thus made to contribute directly to the comfort and convenience of man, in return for the care and attention afforded them. Honey and wax are also obtained from several species of wild bees (Melipona, Trigona, and Tetragona), essentially different from the domesticated kinds. While bees and other hymenopterous insects seek only the gratification of their own inclinations, in their frequent visits to flowers, they carry on their bodies the yellow dust or pollen from one blossom to another, and scatter it over the parts prepared to receive and be fertilized by it, whereby they render an important service to vegetation.

* Now placed among the Proctotrupidæ.

7.-- DIPTERA (Mosquitos, Gnats, Flies, &-c.). Insects with a horny or fleshy proboscis, two wings only, and two knobbed threads, called balancers or poisers, behind the wings. Transformation complete. The larvæ are maggots, without feet, and with the breathing-holes generally in the hinder extremity of the body. Pupæ mostly incased in the dried skin of the larvæ, sometimes, however, naked, in which case the wings and the legs are visible, and are found to be more or less free or unconfined.

The two-winged insects, though mostly of moderate or small size, are not only very numerous in kinds or species, but also extremely abundant in individuals of the same kind, often appearing in swarms of countless multitudes. Flies are destined to live wholly on liquid food, and are therefore provided with a proboscis, enclosing hard and sharp-pointed darts, instead of jaws, and fitted for piercing and sucking, or ending with soft and fleshy lips for lapping. In our own persons we suffer much from the sharp suckers and blood-thirsty propensities of gnats and mosquitos (Culicida), and also from those of certain midges (Ceratopogon and Simulium), including the tormenting black-flies (Simulium molestum) of this country. The larvæ of these insects live in stagnant water, and subsist on minute aquatic animals. Horse-flies and the golden-eyed forest-flies (Tabanida), whose larvæ live in the ground, and the stinging stable-flies (Stomoxys), which closely resemble common house-flies, and in the larva state live in dung, attack both man and

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