of silk; its little downy russet-coloured tents, which are about a quarter of an inch high, and not much thicker than a pin, resemble, at first sight, so many spines growing out of the leaf; but if you pull off one of them, and give it a gentle squeeze, you will see a little yellowish caterpillar, with a black head, emerge from the lower end of it. The strong, white webs too, that frequently disfigure the hedges and fruit trees, are a silken covering, produced by the joint labours of a species of caterpillars, the larvae of the Bombyx Chrysorrhea, and intended as their common residence, under which they may be securely sheltered during their various changes. Indeed the instances are numberless of insects that use silk, either wholly or in part, in the construction of their habitations: whatever other substances be employed in forming the fabric, silk is almost always the cement that fastens them together.

ANNA.-None, however, produce such beautiful

cocoons.

PAPA.-None, perhaps, enrich them with so much beautiful material: the silk worm, in the three days it employs in spinning, produces, at least, three hundred yards of silk but there are several, even in our own country, that form very curious ones. Did you never see those of a species of weevil, the curculio arator, which are frequently found attached to the common spurrey? They very much resemble fine gauze. Many of the saw flies too are remarkable for the cocoons they construct: they form an internal one of a soft, close, flexible texture; which they surround with another composed of a strong kind of net work that effectually secures them from injury during their period of repose in the pupa state.

ANNA.-Do insects remain in the pupa state long?

PAPA. They vary very much in that respect. Some species continue in it only a few hours; others months; and others one or more years. The length of time depends, in some measure, on the warmth of the climate:

the same insects will remain pupæ as long again in our country as they will in India. Your silk-worms, for instance, which you have probably observed to be about a month in escaping from their prisons, would become moths in fifteen days in their natural climate.

ANNA. I always help them as much as I can by snipping open the cocoon when I have wound off the silk.

PAPA. You need not do that; for the moth is provided with a solvent fluid which would enable it very readily to open a passage for itself.

When the insect is disclosed from the pupa it is in all respects different from what it had been before: it often requires no food at all, and scarcely ever more than a very small quantity; indeed its stomach is found to have been very much contracted, in some instances to a tenth of its former bulk: its almost sole object appears to be to make provision for the production of future generations, by depositing its eggs on that substance which is suited for the support of its infant offspring; and having done that, it generally dies. I have much, however, to tell you of its structure and habits during this short but interesting period of its existence. When I have a convenient opportunity, I will indulge you with a sight of my cabinet, and we will converse on the subject more at large.

ANNA. That will indeed be a great pleasure to me: I am more and more anxious to become acquainted with these interesting little beings.

PAPA. The same creature is, you see, in fact, three different animals; and the modes of its existence are often as distinct as those of animals the most distantly related of other tribes. The same insect often lives successively in three or four worlds: at one period it is an inhabitant of water; at another of earth; at a third of air; and in each abode has a form and propensities that adapt it to the offices in the creation it is intended to fulfil.

Z. Z.

DESCRIPTION OF BRITISH TREES.

No. VI.

THE ELM-ULMUS.

THE Elm, like most other trees, does not bear the flower and leaf together, therefore we have drawn it in seed. It will be observed that in our specimen the leaf is long and pointed-in many it is not much longer than it is broad, but still pointed and much notched: this is but a variety of the same species. The flower of the Elm is a small tuft of greenish, yellow flowers, without blossom, coming out on the side of the stems before the leaf; of the Class Pentandria Digynia: the bark is cracked and wrinkled: the leaves are not alike on both sides of the stem, at the base, and they are much notched and veined.

"Columella, in his twelfth chapter de Arboribus, informs us that Elms were principally employed in making living props to vines; and that vineyards formed upon this extensive plan, were named Arbusta, the vines themselves being called Arbustivæ Vites, to distinguish them from others raised in more confined situations. Since the introduction of silk-worms into Italy, the Mulberry-trees in many places are pollarded for the double purpose of supporting vines, and supplying leaves for feeding the worms. Once in two years the Elms were carefully pruned, to prevent their leaves from overshadowing the grapes; and this operation was deemed of great importance. Virgil, in his description of the implements of husbandry, recommends the buris or plough-tail to be made of an Elm bent in the woods-from this is probably taken the hint of forming kneetimber by bending down young Oaks, while growing. Among the ancients, it was customary to plant about their tombs such trees as bore no seeds, particularly the Elm:"

Jove's silvan daughters bade their Elms bestow

A barren shade, and in his honour grow.-VIRGIL.

"The Elm is certainly a native of this country-there can be no stronger proof of it, than that there are near forty places in this kingdom which have their names from it, most of which are mentioned in Domesday-book."-Hunter.

"Of the trees which grow in our woods, there is none which does better suffer the transplantation than the Elm; for you may remove a tree of twenty years' growth with undoubted success: it is an experiment I have made in a tree almost as big as my waist; but then