heart of timber, and in this way many exotic species are conveyed to this country, and are occasionally taken alive in the London and Liverpool docks. Several of the Longicorn Beetles are among the largest of Coleopterous insects, Prionus giganteus measuring 5 inches in length, while its eggs are nearly as large as those of the smaller birds. The Harlequin Beetle (Acrocinus longimanus), so called from the variety of its colouring, the grotesqueness of its markings, and the enormous elongation of its front pair of legs, is a South American species of this group, as is also the Musk Beetle (Callichroma moschata), one of the handsomest of our native species, and remarkable for
the musky odour of its body.
III. Phytophaga comprise the tetramerous beetles which have neither the rostrum of the first group nor the lengthened antennae of the second. They are small insects of an oval or quadrate shape, and include the Golden Beetles, Chrysomelidce (Plate VIII. fig. 21), ornamented with metallic colours, among which blue, green, gold, and coppsr are conspicuous. The Turnip-fly (Ilaltica nemorum], a small species belonging to a family in which the posterior thighs are enlarged for leaping, devours the .young leaves of the turnip as soon as they appear above ground, and occasionally does immense injury to the turnip crop. Helmet or Tortoise Beetles, Cassidce (Plate VIII. figs. 20, 24), so called from the thorax and elytra overlapping so as to shield the limbs and abdomen on all sides, are oval, and in some -cases almost square, flat insects, and often beautifully marked with combinations of green and golden hues, They are herbivorous, and are specially fond of artichoke and thistles. The larvae are provided at the posterior extremity with a two-branched fork, curved over the back, and usually bsaring a pile of excrementitioug matter, under which they lie partly concealed It can elevate or depress this stercoraceous parasol at pleasure, according as it needs shade or shelter. The Colorado Potato Beetle (Doryphora decemlineata) belongs to the phytophagous family Chrysomelidce. It measures nearly half an inch in length ; its body is of a tawny or yellow cream colour, darkly spotted ; and the elytra are marked with ten black longitudinal stripes. It is a native of the eastern slopes of the Rocky Mountains, where it fed on a wild solanaceous plant, Sulanum rostratum, until the introduction of the potato plant, consequent on the settle ment and cultivation of the " Far West," provided it with what appears to have been a more appropriate food. Since 1859 it has travelled eastward, towards the more highly cultivated lands, at the rate of nearly 100 miles per annum, until it has reached the Atlantic Coast. It is now found over all the central and northern parts of the United States east of the Rocky Mountains, and throughout Canada, and lias already done incalculable mischief to the potato crops i>f those regions. The damage is chiefly wrought by the larvae, which are hatched on, and greedily devour, the leaves and stalk of the potato plant. They are said to produce three broods annually.
Trimera.—The majority of the beetles composing this section have only three apparent joints to the tarsi of all the feet, but a small articulation has been found to lie be tween the second and third joints, so that they are in reality four-jointed, and for this reason Westwood has changed the name of the section to Pseudotrimera.
Trimerous beetles form a single group, the species of which are partly herbivorous, feeding on fungi (Plate VIII. figs. 17, 18), and partly carnivorous, devouring aphides or plant lice. The most familiar examples of this group are Lady-birds, Coccindlidce (Plate VIII. fig. 23), small con vex insects of a black colour, spotted with red or yellow, >r of a reddish colour, spotted with black. The larvae do great service by devouring the plant lice, which usually infest garden bushes. When alarmed the Lady-birds retract their limbs and emit a yellow juice from their joints, which has a very disagreeable odour. They occasionally occur in great numbers, extending for miles, in the south-eastern districts of England, where they are invaluable for freeing the hops of aphides. They walk slowly but fly well. The Seven-Spotted Lady-bird (Ooccinella 7-pundata), the com- inon species of Britain, is found in all quarters of the globe.
On Collecting and Preserving Coleopterous Insects.—The collector of beetles, in order to obtain perfect specimens, need not have recourse to the plan adopted by the lepidopterist of rearing the insect from the egg. Tlia successful rearing of these is much more difficult than in the case of butterflies and moths, and the specimens so procured are generally inferior to those collected in tho ordinary way. The complete life history, however, of com paratively few even of our native species has yet been fully traced ; and although the collector thus might not greatly enrich his cabinet with specimens of his own rearing, yet by adopting this method he would almost certainly add to the general stock of knowledge regarding the transforma tions of these insects. Beetles may often be obtained in what may be termed accidental situations, sand-pits into which they have fallen, or artificial traps set for them, as a white sheet spread on the grass; but "sweeping" and "beating " are the means mainly relied on by the coleopterist for filling his cabinet, and for these all the apparatus neces sary consists of an umbrella-net and a stick for beating. The net is swept over the grass, and among the foliage of trees, and when the branches are shaken with the hand, or beaten with the stick, the net is held beneath to catch the falling insects. An umbrella inverted, or a sheet placed beneath the tree, serves the same purpose. A knowledge of the habits of the various tribes of beetles will give the collector a clue to the localities in which, and the time when, he may expect to find the species he is in search of. In this way the bark and timber of trees, decaying branches and leaves, putrescent fungi, the droppings and the dead bodies of mammals, fresh water ponds, and even the nests of wasps, bees, and ants will all be found to yield their own harvest of Coleoptera. Beetles when caught may either be dropped into a phial containing spirits of any kind, or into what is known as the " killing bottle," the bottom of which contains cyanide of potassium covered over with a layer of gypsum. In either case, with few exceptions, the beetles die almost instantaneously. If kept too long in spirits, however, the limbs get loosened through maceration and fall off. The "setting" of a beetle, or of any other insect, consists in placing its limbs and antennae in a natural position and fixing them there by means of pins until they stiffen on a board on which there is a layer of cork. If not set when either moist or recent, they may be softened by being placed for a night in any small vessel containing a layer of wet sand, and covered with a damp cloth to prevent evaporation. The smaller beetles are usually mounted on card, each insect being stuck on a small dab of gum with its legs and antenna?- properly set ; all others are pinned through the centre of the upper part of the right elytron. In the case of large beetles as much of the contents of the body as possible should be removed by making an opening in the abdomen ; and with the Oil Beetles it is necessary to stuff the abdomen. This can be best effected by separating the latter from the body, emptying it, and refilling with wadding ; it can then be readily gummed to the body. Mould may be got rid of by exposing the specimens to a strong heat for some hours, and mites and grease by washing the beetles with a small brush dipped in benzine.
(j. gi.)
