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hol is a most effectual method. As soon as the operation is properly per• formed, the depredating insect perceives that the prepared specimen is no longer food for it, and will for ever cease to attack it. But, then, every part must have received the poison; otherwise those parts where the poison has not reached will still be exposed to the enemy; and he will pass unhurt over the poisoned parts, till he arrive at that part of your specimen which is still wholesome food for him. Now, the difficulty lies in applying the solution to very minute specimens, without injuring their appearance; and all that can be said is, to recommend unwearied exertion, which is sure to be attended with great skill; and great skill will insure surprising success. I myself have attended to the preservation of insects with the assiduity which Horace recommends to poets :-"Nocturna versate manu, versate diurna." The result has been astonishing success, and a perfect conviction that there is no absolute and lasting safety for prepared specimens, in zoology, from the depredations of insects, except by poisoning every part of them with a solution of corrosive sublimate in alcohol. I put a good large teaspoonful of well pounded corrosive sublimate into a wine bottle full of alcohol. I let it stand over night, and the next morning draw it off into a clean bottle. When I apply it to black substances, and perceive that it leaves little white particles on them, I then make it weaker by adding alcohol. A black feather, dipped into the solution, and then dried, will be a very good test of the state of the solution. If it be too strong, it will leave a whiteness upon the feather.

A preparation of arsenic is frequently used; but it is very dangerous, and sometimes attended with lamentable consequences. I knew a naturalist, by name Howe, in Cayenne, in French Guiana, who had lost sixteen of his teeth. He kept them in a box, and showed them to me. On opening the lid - "These fine teeth," said he, " once belonged to my jaws: they all dropped out by my making use of the savon arsenetique for preserving the skins of animals." I take this opportunity of remarking that it is my firm conviction, that the arsenetical soap can never be used with any success, if you wish to restore the true form and figure to a skin.

I fear that your correspondent may make use of tight boxes and aromatic atmospheres, and still, in the end, not be completely successful in preserving his specimens from the depredation of insects. The tight box and aromatic atmosphere will certainly do a great deal for him; but they are liable to fail, for this obvious reason, viz. that they do not render, for ever, absolutely baneful and abhorrent to the depredator, that which in itself is nutritious and grateful to him. In an evil hour, through neglect in keeping up a poisoned atmosphere, the specimens collected by your correspondent's industry, and prepared by his art, and which ought to live, as it were, for the admiration of future ages, may fall a prey to an intruding and almost invisible enemy: so that, unless he apply the solution of corrosive sublimate in alcohol, he is never perfectly safe from a surprise. I have tried a decoction of aloes, wormwood, and walnut leaves, thinking they would be of service, on account of their bitterness: the trial completely failed. Wherefore, in conclusion, I venture to recommend to your correspondent not to put much trust in simples.

"Contra vim mortis, non est medicamen in hortis."

"Against the deadly moth, can I,
From herbs, no remedy supply."

Charles Waterton. Walton Hall, June 9. 1832.

The Tail of the Caterpillar becomes the Head of the Butterfly (p. 206. 398.). Sir, The caterpillar of the genus Psyche, figured by Mr. Curtis, in his British Entomology (pl. 332.), is enclosed in a case, and is frequently to be seen on trunks of trees, and on rocks, where it changes to a pupa. The

head part is fastened to the tree or rock, but the moth escapes at the opposite or tail part; but whether it backs out, or acts the part of the lady's pony, as facetiously adverted to in p. 398., I have not discovered, and have therefore enclosed you a specimen (fig. 119. a) of the pupa, with

d

119

the exuvia at the opposite end to that by which the pupa is fastened. I suspect that the circumstances are the same with the pupa of some Tineæ, of Oikéticos of Guilding, in Lin. Trans. (vol. xv. tab. 6.), and with the Penthophera? mentioned at p. 252. of your current volume. One of my larvæ of Penthóphera? in the case, as spoken of in your p. 252., lies motionless, and, I suspect, is in pupa (I send you a sketch of its present appearance, b); the other began to move early in the spring, and is now a larva on a sprig of birch: but I could not see that it had eaten (since it ceased eating in the autumn) until lately, when it ate a very little. Two or three specimens of the pupa (b) of this insect were found, last autumn, near Heron Court, Hants, and given to Mr. Curtis, by the Honourable C. A. Harris. I am, Sir, yours, &c.-J. C. Dale. May, 1832.

Mr. Dale's favour was received through the hands of Mr. Curtis, who obligingly stated that the pupa case sent by Mr. Dale, and represented in our figure (a), assimilates closely to that of Psyche nitidélla of Hübner, which Mr. Curtis has copied, and incidentally exhibited on his plate 332.; and which we have again copied, from Mr. Curtis's plate, in our figure (c). The professed subject of Mr. Curtis's plate 332. is Psyche radiélla of Curtis, and his figure of this insect we have copied in our figure (d); and Mr. Curtis hints that it is possible that the pupa case sent us by Mr Dale, and represented in our figure (a), is the pupa case of this Psyche radiélla Curtis. The pupa case, of which Mr. Dale sent us a sketch (b), Mr. Curtis suspects may be the pupa case of the Penthóphera nígricans of his British Entomology (pl. 213.): the case is fabricated mainly of small portions of the branches of the common ling (Calluna vulgaris Sal., Erìca vulgàris L.) The pupa cases of these two insects (Psyche radiélla Curtis, and Penthophera nígricans) have never yet been figured, or to a certainty met with: we hope, therefore, should the pupa cases represented in our figures (a and b) develope these insects, Mr. Dale will be so obliging as to tell us so; or, if they develope insects of other species, as to tell us all he can about them. From the able description and notices supplied by Mr. Curtis, to his figure of Psyche radiélla Curtis, in his British Entomology (pl. 332.), the following remarks, very valuable in themselves, and pertinent to the question at issue, are quoted.-J. D.

"Ochsenheimer [a most accurate observer of nature] makes some curious observations respecting our insects: he says the male caterpillar turns round in his case, or sack, before changing to a pupa, in order to be able

to creep out at the hinder opening: this becomes necessary, I suppose, from the case being firmly attached by the other end to a leaf or tree. He also says, that virgin females sometimes lay fruitful eggs." "It is a very extraordinary fact, that the group of moths to which Psyche belongs makes, in more than one respect, a near approach to the Phryganida; and, I think, they will be made eventually to connect the orders of Trichoptera and Lepidoptera; for, whether we consider the larvæ and their remarkable economy, or the form of the perfect insects and the substance with which they are clothed, the resemblance is most striking. It will, however, require considerable additions of the Trichoptera to our cabinets, as well as a better knowledge of the structure of those we already possess, before this change can be safely attempted."

The Tail of the Caterpillar becoming the Head of the Butterfly. (p. 206. 398, 399.) — Sir, Your correspondent T. C. (p. 206.) is most certainly in an error when he states this to be a fact. I know not what species he refers to; but, whatever it may be, such a change is hardly possible. The Vanessa genus, when full fed, spin a kind of silk button, as shown in Insect Transformations (p. 274.), to which the caterpillar fixes itself by the tail, and hangs with the head downwards, generally a day, and sometimes nearly two days, before the change to the chrysalis takes place. The skin begins to split at the lower end, or head of the caterpillar, where the head of the chrysalis is first developed, and, by degrees, is worked upwards, till it is entirely disengaged at the tail end. The chrysalis then fixes its tail to the silk button, and hangs securely till the fly is bred, which is in about fourteen or sixteen days, if the weather proves warm. The outline of the wings and antennæ may be easily distinguished in the chrysalis; and, a day or two before the butterfly appears, the colours of its wings may be seen through the thin shell, showing that the head of the insect continues in the same position. When the fly bursts from the chrysalis, it comes out at the bottom, bends itself upwards, and clings by its feet to the chrysalis, drawing out the rest of its body; and now, for the first time, after tying itself up, is the insect in a position with its head uppermost : here it rests till the wings are expanded, which, I have observed in the Vanessa urticæ, is in about ten or twelve minutes after the fly comes out, though they do not acquire sufficient strength, in that time, to enable the insect to fly, being at first soft and flabby, like wet paper. I have bred numbers of the peacock and small tortoiseshell butterflies, but in no instance could I discover the tail of the caterpillar changing into the head of the butterfly. I would recommend T. C. to procure some of these caterpillars, which he wil doubtless find plentiful on the great stinging nettle (Urtica dioica Lin), in July, and put them in a breeding-cage, with some of their favourite food: he will then have an opportunity of observing correctly the manner in which they change: and that it is not the tail of the caterpillar which becomes the head of the butterfly.-T. G. Chipping Norton, Oxfordshire, May 15. 1832.

An English Work descriptive of the Species of British Insects wanted, — Sir, Is there any moderately priced book on British Entomology, by which I may learn to affix to my specimens their proper scientific names? I am aware there are many such in Botany, and can hardly suppose there are none such in Entomology. The publications of Curtis and of Stephens, though affording the information I want, are too expensive to come within my reach. Tyro. March 24. 1832.

Humming in the Air. (p. 110. 301.) — To O.'s query and suggestions on this subject, I beg to contribute some observations. No one who has resided in the country, or has walked on an open field or common on a cain summer day, but must have been struck with this truly rural sound. The poet Thomson notices it, with his usual elegance and accuracy:

"Resounds the living surface of the ground:
Nor undelightful is the ceaseless hum

To him who muses through the woods at noon;
Or drowsy shepherd, as he lies reclined,

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beneath the floating shade

Of willows grey."

Summer.

That the vibrations of innumerable wings of insects "resounds" from the surface of the ground, is certainly true; but that the "ceaseless hum" heard in the air proceeds from a numerous congregation of one sort of fly, is equally a fact. Although I have lived by far the greater part of my life in the country, it was a period of many years before I discovered the real cause of this continuous hum in the air. I accustomed myself to attribute it to the sound from the wings of bees, and all other insects passing and repassing near the spot where I stood; till, on one occasion, while I was passing over an open eminence in a well wooded country, this hum was so audible that I thought a swarm of bees was passing over-head: on looking up, I saw no bees, but an innumerable swarm of flies disporting in the sunbeams, at the height of 50 or 60 ft. from the ground. This I afterwards found to be an assembly of the sexes; not so closely thronged together as to be collectively visible, but flying in very open order in all directions, and in most rapid motion; requiring a keen sight to discern them, either collectively or individually. Their height from the ground, and rapidity of flight, are the causes of their eluding the sight of those who know not where to look for the source of this fairy-like sound, but a strong and steady eye will readily detect the humming throng. I paid attention, afterwards, to their movements, and discovered, that, after passing the greater part of the day in the air, they descend to the woods, where they may be both heard and seen, basking on the sunny side of the trunks of trees, just before sunset. It is nearly twice the size of the common house-fly, and exactly of the same form and colour. In autumn it enters houses, and is often found laid up for the winter in the valance of bed and window curtains.-J. M.

The Caterpillar of the Broom Moth eats the Petals of Flowers in preference to Herbage. How is it defended from the Spines of Furze, as it is devoid of a hairy Covering like Arctia Càja, the Garden Tiger? And is not the Covering of the Bombyx Caja subservient to its Defence? Sir, The incidental mention, at p. 68., of the broom moth (Chèsias spartiàta Stephens) leads me to communicate the following notice and queries respecting it :

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In 1830, I captured a considerable number of caterpillars of this species on the common furze (Ulex europæ`a), when that plant was in full bloom. I remarked nothing singular in their feeding at the time; and took home with me some young furze shoots, without blossoms, for them to eat. I put them, with their food, into a breeding-box; and, after some time, came to see how they were going on, but not a bit had they touched. I thought they might not be quite reconciled to their situation, as they seemed very restless; so I left them to themselves. The next day it was the same. then sent for some fresh furze; and they brought me some with blossoms, which I placed in the box instead of the other: in a very short time they had eaten every blossom, while the thorny part they had left untouched, as before.

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It is well known how wonderfully the larvae of the common tiger moth (A'retia Caja) are defended against the nettle's sting; but those of the broom moth are, to all outward appearance, entirely unprovided against the dangerous thorns among which they feed. Their skin is like velvet to the touch; but, notwithstanding, I have seen them lean their whole weight on the sharpest point without the least injury. Is it, then, from the elas

ticity and toughness of the skin that they are thus enabled to make their way through such a "cheval de frise" of thorns? or have the long hairs nothing to do with defending the body of the tiger moth? If any one of your readers would give me more information on these subjects, I should be much obliged. I am, Sir, yours, &c. - Bómbyx. Feb. 3. 1832.

If the caterpillar of the garden tiger be molested when feeding at considerable height from the ground, it makes no scruple, by a vigorous contortion, to release itself from molestation, to throw itself to the earth; perhaps in the consciousness that its long elastic hairs will preserve it from all injury by concussion. It will be scarcely possible to apply to the hairs of this caterpillar the solution that has been, in the Library of Entertaining Knowledge, so admirably offered of the utility to the cat of its whiskers. J. D.

A Meteorological Calendar; the best Formulary and Instruments for. — E. H. G. asks for information on these points, and further, asks the names of the makers of, and, if agreeable, their prices for the instruments recommended; cheapness being a consideration. The name and price of " any good and cheap elementary work on the subject" will also be valued.

We leave to our meteorological correspondents the majority of E. H. G.'s queries; but respecting a formulary, we may remark, that the best we have seen is one sent us by our valued correspondent, Sigma, but to whom we have been under the necessity of returning it, as its form was too expensive for being printed, and because we are, for the present at least, scarcely desirous of more meteorological journals. The calendar mentioned was of this form: :-- A sheet of paper was divided into perpendicular columns, as various in width as the following subjects, with which the columns were respectively and successively headed, required: 1st column, the month; 2d, the day of the month; 3d, height of the thermometer at night; 4th, height of the thermometer by day; 5th, indications of the barometer; 6th, lunation; 7th, state of wind in the forenoon; 8th, state of wind in the afternoon, and the 9th, 10th, 11th, and 12th were ascribed to atmospheric variations; the 9th column the state of the atmosphere at 8 o'clock in the morning; the 10th, to its state at noon; the 11th, to its state at 8 o'clock in the evening; the 12th, to its state at night; the 13th column, a broad one, contains the prevailing form of clouds; the 14th, a broad column, to the appearance of birds, insects, &c., whether solitary, few, or numerous; 15th, a broad column for first appearance of flowers, and notices of their state, as to whether in bud, in full flower, &c.; 16th and last, a broad column also, for general remarks. By the help of a few abbreviations, this calendar by Sigma was rendered admirably comprehensive, and what excited our preference for it is, that by such a tabular and synoptical exhibition of the details, all of them could be seen in one view, and, as you might desire, either in connection or contrast. The influence of the atmosphere's condition on organised nature is by this mode very intelligibly, and therefore instructively, shown. The only addition which it occurs to us to suggest is, that, as far as ascertainable, the state of the health of the human inhabitants of the neighbourhood should be from time to time stated, as far as the successive states of health might be deemed consequent on atmospheric action (see p. 350.).—The above had been written previously to the third of April (1832), at which date was exhibited, at a meeting of the London Horticultural Society, "a sentinel thermometer, regulated by the expansion of air acting upon a delicate mercurial balance, invented by Mr. John Lindley." This instrument we have not seen, but the present mention of it will supply a clew to any one desirous to learn more about it.-J. D.

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