OBSERVATIONS ON INSECTS. 317 I do not ever remember to have seen such swarms, except in the fens of the Isle of Ely. They appear most over grass grounds. APHIDES. On the first of August, about half an hour after three in the afternoon, the people of Selborne were surprised by a shower of aphides which fell in these parts. They who were walking the streets at that time found themselves covered with these insects, which settled also on the trees and gardens, and blackened all the vegetables where they alighted. These armies, no doubt, were then in a state of emigration, and shifting their quarters; and might perhaps come from the great hop plantations of Kent or Sussex, the wind being_that day at north. They were observed at the same time at Farnham, and all along the vale at Alton. ANTS.-August 23.- Every ant-hill about this time is in a strange hurry and confusion; and all the winged ants, agitated by some violent impulse, are leaving their homes, and, bent on emigration, swarm by myriads in the air, to the great emolument of the hirundines, which fare luxuriously.* Those that escape the swallows return no more to their nests, but, looking out for fresh settlements, lay a foundation for future colonies. All the females at this time are pregnant; the males that escape being eaten, wander away and die. October 2. Flying ants, male and female, usually swarm and migrate on hot sunny days in August and September; but this day a vast emigration took place in my garden, and myriads came forth, in appearance from the drain which goes under the fruit wall; filling the air and the adjoining trees and shrubs with their numbers. The females were full of eggs. This late swarming is probably owing to the backward wet season. The day following, not one flying ant was to be seen. Horse ants travel home to their nests laden with flies, which they have caught, and the aurelia of smaller ants, which they seize by violence. † While the ants are a prey to swallows, they, in their turn, prey upon other insects; that troublesome vermin, the aphides, are devoured in millions by ants, whose hills are near the bushes on which the aphides feed. Ants eat all kinds of animal food. Ed. + In my Naturalist's Calendar for the year 1777, on September 6th, I find the following note to the article, Flying Ants: I saw a prodigious swarm of these ants flying about the top of some tall elm trees close by my house: some were continually dropping to the ground as if from the trees, and others rising up from the ground: many of them were joined together in copulation; and I imagine their life is but short; for as soon as produced from the egg by the heat of the sun, they propagate GLOW-WORMS- By observing two glow-worms which were brought from the field to the bank in the garden, it appeared to us, that these little creatures put out their lamps between eleven and twelve, and shone no more for the rest of the night.* Male glow-worms, attracted by the light of the candles, come into the parlour. EARTH-WORMS.- Earth-worms make their casts most in mild weather, about March and April; they do not lie torpid in winter, but come forth when there is no frost. They travel about in rainy nights, as appears from their sinuous tracks on the soft muddy soil, perhaps in search of food. When earth-worms lie out a-nights on the turf, though they extend their bodies a great way, they do not quite leave their holes, but keep the ends of their tails fixed therein, so that, on the least alarm, they can retire with precipitation under the earth. Whatever food falls within their reach when thus extended, they seem to be content with,- such as, blades of grass, straws, fallen leaves, the ends of which they often draw into their holes; even in copulation their hinder parts never quit their holes so that no two, except they lie within reach of each other's bodies, can have any commerce of that kind; but, as every individual is a hermaphrodite, there is no difficulty in meeting with a mate, as would be the case were they of different sexes. SNAILS AND SLUGS.. The shelless snails called slugs are in motion all the winter, in mild weather, and commit great depredations on garden plants, and much injure the green wheat, the loss of which is imputed to earth-worms; while the shelled snail, the pegsoxos, does not come forth at all till about April 10th, and not only lays itself up pretty early in their species, and soon after perish. They were black, somewhat like the small black ant, and had four wings. I saw also, at another place, a large sort which were yellowish. On the 8th of September, 1785, I again observed the same circumstance of a vast number of these insects flying near the tops of the elms, and dropping to the ground. On the 2d of March, 1777, I saw great numbers of ants come out of the ground. MARKWICK. * The male glow-worm yields light as well as the female, but much fainter. The eggs are also, in some degree, luminous. The light, which the worm has power to extinguish at pleasure, proceeds from brilliant spots on the three last rings of the body, and on the tail; the luminous matter is a yellow substance contained in the vesicles; and when these vesicles are removed entire, they shine for some time afterwards; but if lacerated, they are extinguished. ED. OBSERVATIONS ON INSECTS. 319 autumn, in places secure from frost, but also throws out round the mouth of its shell a thick operculum formed from its own saliva; so that it is perfectly secured, and corked up, as it were, from all inclemencies. The cause why the slugs are able to endure the cold so much better than shell-snails is, that their bodies are covered with slime, as whales are with blubber. * Snails copulate about midsummer; and soon after deposit their eggs in the mould, by running their heads and bodies under ground. Hence, the way to be rid of them is, to kill as many as possible before they begin to breed. Large, gray, shelless cellar snails, lay themselves up about the same time with those that live abroad: hence, it is plain, that a defect of warmth is not the only cause that influences their retreat. SNAKE'S SLOUGH. There the snake throws her enamel'd skin. SHAKESPEARE's Mids. Night's Dream. About the middle of this month (September) we found, in a field near a hedge, the slough of a large snake, which seemed to have been newly cast. From circumstances, it appeared as if turned wrong side outward, and as drawn off backward, like a stocking, or woman's glove. Not only the whole skin, but scales from the very eyes, are peeled off, and appear in the head of the slough like a pair of spectacles. The reptile, at the time of changing his coat, had entangled himself intricately in the grass and weeds, so that the friction of the stalks and blades might promote this curious shifting of his exuviæ. It would be a most entertaining sight, could a person be an eye-witness to such a feat, and see the snake in the act of changing his garment. As the convexity of the scales of the eyes in the slough is now inward, that circumstance alone is a proof that the skin has been turned: not to mention that now the present inside is much darker than the outer. If you look through the scales of the snake's eyes from the concave side, viz. as the reptile used them, they lessen objects much. Thus it appears, from what has been said, that snakes crawl out of * Slugs have the property of spinning a slimy thread, whereby they can let themselves down from a height in the manner of spiders. - En. the mouth of their own sloughs, and quit the tail part last, just as eels are skinned by a cook maid. While the scales of the eyes are growing loose, and a new skin is forming, the creature, in appearance, must be blind, and feel itself in an awkward, uneasy situation.* OBSERVATIONS ON VEGETABLES. TREES, ORDER OF LOSING THEIR LEAVES. ONE of the first trees that become naked is the walnut; the mulberry, the ash, especially if it bears many keys, and the horse-chestnut come next. All lopped trees, while their heads are young, carry their leaves a long while. Apple trees and peaches remain green very late, often till the end of November; young beeches never cast their leaves till spring, till the new leaves sprout and push them off: in the autumn, the beechen leaves turn of a deep chestnut colour. Tall beeches cast their leaves about the end of October. SIZE AND GROWTH.-Mr Marsham of Stratton, near Norwich, informs me by letter thus: "I became a planter early; so that an oak which I planted in 1720 is become now, at one foot from the earth, twelve feet six inches in circumference, and, at fourteen feet, (the half of the timber * I have seen many sloughs, or skins of snakes, entire, after they have cast them off; and, once in particular, I remember to have found one of these sloughs so intricately interwoven amongst some brakes, that it was with difficulty removed without being broken: this undoubtedly was done by the creature to assist in getting rid of its encumbrance. I have great reason to suppose that the eft, or common lizard, also casts its skin, or slough, but not entire like the snake; for, on the 30th of March, 1777, saw one with something ragged hanging to it, which appeared to be part of its old skin.—MARKWICK. It has been found by Pallas, that, after leeches have been used for medicinal purposes, they are most reproductive. He puts them into a box with argillaceous earth, six inches deep, at any time from the middle of August till the end of September. In five months, cocoons will be found, each containing twelve individuals. The cocoons are, on the outside, light, porous, and wooly, to keep out moisture and regulate the temperature. On the inside they are fibrous and dense, enclosing a thin multilocular pellicle, which contains germs. -ED. OBSERVATIONS ON VEGETABLES. 321 length,) is eight feet two inches. So, if the bark were to be measured as timber, the tree gives one hundred and sixteen and a half feet, buyer's measure. Perhaps you never heard of a larger oak, while the planter was living. I flatter myself that I increased the growth by washing the stem; and digging a circle, as far as I supposed the roots to extend, and by spreading sawdust, &c. as related in the Phil. Trans. I wish I had begun with beeches, (my favourite trees, as well as yours ;) I might then have seen very large trees of my own raising. But I did not begin with beech till 1741, and then by seed; so that my largest is now at five feet from the ground, six feet three inches in girth, and, with its head, spreads a circle of twenty yards diameter. This tree was also dug round, washed, &c. Stratton, 24th July, 1790." The circumference of trees planted by myself, at one foot from the ground, (1790 :) The great oak in the Holt, which is deemed by Mr Marsham to be the biggest in this island, at seven feet from the ground, measures, in circumference, thirty-four feet. It has, in old times, lost several of its boughs, and is tending to decay. Mr Marsham computes, that, at fourteen feet length, this oak contains one thousand feet of timber. It has been the received opinion, that trees grow in height only by their annual upper shoot. But my neighbour, over the way, whose occupation confines him to one spot, assures me, that trees are expanded and raised in the lower parts also. The reason that he gives is this: the point of one of my firs began, for the first time, to peer over an opposite roof at the beginning of summer; but, before the growing season was over, the whole shoot of the year, and three or four joints of the body beside, became visible to him, as he sits on his form in his shop. According to this supposition, a tree may advance in height considerably, though the summer shoot should be destroyed every year. FLOWING OF SAP. If the bough of a vine is cut late in the spring, just before the shoots push out, it will bleed considerably; but, after the leaf is out, any part may be taken |