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ART. V. On the Injury produced to Plantations of Sallows and Osiers (Sálices), and Loss of Gain to the Proprietor, by the Ravages, on the Foliage of these Plants, of the Caterpillars of the Insect Nématus càprea F.: with a Notice, in Sequel, of the very great Importance of a Scientific Knowledge of Natural Objects to those engaged in the Practices of Rural Economy. By C. D.

I OBSERVE, in p. 265., a short notice of Nématus càpreæ. I am very little, indeed, of a naturalist; but, having suffered from the ravages of this insect, my attention has been drawn to its acts and habits; and the results of my experience may be, perhaps, useful to others. I have a piece of moist ground, in a low sheltered situation, highly favourable in itself for the growth of osiers. I remember it, as first known to me about thirty years ago, when some straggling osier bushes were growing upon it, and it was covered in other parts with weeds and brambles. On the offer of an opportunity, about twenty years since, I determined on cultivating the spot well, and then planting it with osier plants. A sort of tradition prevailed, that osiers would never succeed there. This I disregarded, deeming it absurd, since they grew freely in very inferior situations in the neighbourhood. The ground was thoroughly dug and then planted. After a few years, the osiers had disappeared, we hardly knew how. The spot was again planted, and with a like result. The ravages of the insect were now noticed, indeed, but still they did not sufficiently attract our attention; and osier plants were actually put in a third time. My attention being now strongly drawn to the subject, I discovered that which ought to have been perceived half a century sooner, namely, that Nématus càpreæ, favoured by the peculiar localities, was the cause of all this devastation. The spot is low, moist, shut in by wood, and very near the southern limit of England. The species of willow planted was chiefly one of those with broad leaves, woolly underneath. The warmth of the situation, and the nidus for eggs afforded by these woolly leaves, were, I presume, the combined cause of the insect being so remarkably attracted to this spot. Some of the plants were of a species with smooth narrow leavest: these escaped much longer

* [Most probably the Salix càprea L. "The name caprea seems to have originated in the reputed fondness of goats for the catkins."-Smith. The specific epithet of the insect, Nématus càpreæ F., was doubtless intended to teach the fact, that the foliage of Salix càprea L., and, it may be assumed, that of allied species, as well (all called sallows in some parts of England), is the favourite food of this insect in the larva state.]

[Salix triándra, amygdálina, Forbyana, rùbra, purpùrea, Hèlix, and Lambertiana, are species of osier, natives of Britain: of this kind, the first four include the species more extensively cultivated in English osier plantations, called, in some places, holts.]

than the others, but still they did not escape eventually: they were also attacked by another caterpillar.

I introduced both red and black ants, and also put some of the caterpillars into their nests; but the ants disregarded them altogether. Having, although thus slowly, ascertained the true state of things, the ground was once more cultivated, and was planted with apple trees. As there happens to be no insect there which much attacks these, they thrive very well. The distance at which apple trees are planted is also less favourable to the propagation of vermin.

I have communicated all this detail, in order to show the importance, to individuals, of attending to such seemingly trifling matters. Many a plantation, &c., fails in an apparently inexplicable manner. A scientific investigation would, in numerous cases, disclose the truth, and prevent farther loss. Had a person acquainted with entomology been proprietor of this osier ground fifty years since, he would speedily have discovered the truth, and might have saved 2001. or more to himself and his successors.

Wireworms. I take this opportunity of mentioning the wireworm. This neighbourhood has been repeatedly ravaged by it. Crops of wheat and potatoes have suffered severely, but the pastures have never been touched. We have no old meadow, and our lands are always broken up when three or four years old. The beetle and its habits are not sufficiently known. If some popular knowledge on these destructive insects could be conveyed to farmers and labourers, they might, perhaps, be destroyed on a large scale.

Penzance, June 18. 1834.

THE facts communicated by C. D. on the habits of the Nématus càpreæ are a welcome furtherance of our knowledge of the natural history of that insect; and they, in conjunction with C. D.'s remarks, are, we conceive, of emphatic value, as exemplifying to entomologists how much their aid in elucidating popularly the forms, structure, transformations, habits, and names of insects is wanted by persons engaged in the businesses of rural life, and also as intimating to them some idea of the extent to, and mode in, which the required aid should be rendered. A remembrance of the nature of our own wants in things entomological, as experienced while engaged in rural practices, and, added to this, some knowledge of the wants of others so engaged, tempt us, therefore, to join C. D. in soliciting entomologists (which C. D. does, in effect) to do, forthwith, what they can, towards leading us, as

farmers, gardeners, orchardists, foresters, intendants of cattle, &c., to the knowledge we so much desire, and so certain to avail us greatly, not only in a pecuniary relation (perhaps, the least worthy regard of all the relations), but in the excellent and best one of intellectual exercise, or mental gratification.

The means by, and the mode in, which this could best be done, is, we have thought, the production of a work which should supply such information on the species of insects eminently injurious, and those eminently beneficial, to rural interests, as is supplied on the plants to which these qualities appertain, in Martyn's Flora Rustica (in which the species of plants described and treated of are identified by figures), and in Holditch's Essay on the Weeds of Agriculture. It may be urged, that very much of the suggested information, and wellnigh all that entomologists possess, has been already placed on record by them, for the public benefit. This may be true; but it is also true that the places of record are too various, and the access to the whole of them a matter too consumptive of time and money, for many rural practitioners to indulge in. It is needless to remark, that every technicality which could be spared, should be kept out of such a work; and the more nearly it could be written in the phraseology of ordinary life, it would be, we think, so much the better. Should woodcuts be deemed sufficient (to spare coloured figures) for the purpose of identifying each species, they would be much to be preferred, as being introducible amongst the text, and thus to be viewed at once without the distraction of a distant reference. In the descriptive matter, it would be well to indicate what facts require to be confirmed by additional testimony, and what points in the economy of each insect remain yet to be explored; and thus the practical man, in appropriating the researches of the entomologist, might be induced to return the result of his own, and might, while he appropriated the fruit of the researches of the entomologist, be instigated to institute others for himself, and to contribute the result of them to the general store. The publication of Notes on such a work would, it is possible, be scarcely less common than Notes on White's Selborne; and, out of each of them, something of truth and means of completeness would surely be acquirable. Neither can it be fallacious or ungratifying to presume that such a work would tend very much indeed to the extension of the studying of insects in an entomological manner. Every accurately represented and described species would make known one of a certain type of form and structure, and lead the way to assimilation and association. Under the description of each of the species, something of the leading points of affinity might perhaps be guardedly hinted.-J. D.

ART. VI. On the most advisable Methods for discovering Remedies against the Ravages of Insects; and a Notice of the Habits of the Onion Fly. By J. O. WESTWOOD, Esq. F.L.S. &c. Read before the Entomological Society, May 5. 1834.

ONE of the most common, and at the same time most weighty, charges brought against the entomologist is, that, whilst he bestows endless labour and trouble on collecting and preserving various kinds of insects, his attention is never, or but very seldom indeed, directed to enquiries into the most effectual remedies for those insect scourges which nature has inflicted upon our vegetable productions. He is told, over and over again, that, to make the science which he cultivates more beneficial to society, and thereby more generally known, a share of his attention must be occupied in prosecuting experiments for the purpose of discovering how this or that insect enemy may be combated in the most successful manner. And, indeed, it must be admitted, that this is a charge too well founded; although, perhaps, a few observations may convince those who are the most ready to bring it forward at every opportunity, that it may be very greatly palliated.

In the first place, therefore, it may be urged, that these destructive insects, appearing, as they do, in occasional seasons, in vast profusion, are produced in such myriads, for some wise purpose, which we may not be permitted to understand. They, like the locusts, of which so splendid a poetical description is recorded in the second chapter of the prophet Joel, form portion of the army of the Almighty, wherewith he scourges the nations; and, although the scientific researches of mankind might discover means of destroying in some degree their hosts, it may, perhaps, not unreasonably be supposed either that he would not be allowed to frustrate the designs of Providence, or that, if this evil were removed, others, perhaps more weighty, might arise in their stead.*

[Man, it is true, fails occasionally to secure to himself all the fruits of his own sowing; but, nevertheless,

"His portion in the good that Heaven bestows"

is undeniably a munificent one. In relief of his partial losses, no sentiment is perhaps more healthy and more just than the unflattering one of our great moral poet, Pope:—

"Has God, thou fool, work'd solely for thy good,
Thy joy, thy pastime, thy attire, thy food?
Who for thy table feeds the wanton fawn,
For him as kindly spreads the flow'ry lawn.
Is it for thee the lark ascends and sings?
Joy tunes his voice, joy elevates his wings.
Is it for thee the linnet pours his throat?
Loves of his own and raptures swell the note.

In the second place, the minuteness of the size of these creatures presents an almost insurmountable barrier against those delicate enquiries and observations on every stage of their existence, by which alone we can arrive at a knowledge of the real nature and cause of the mischief, and be thereby, and thereby alone, enabled to judge of a suitable remedy.

In the third place, the want of sufficient opportunity is not the least objection which may be brought against the charge. It has always appeared to me, that no effectual check can be given to the ravages of any insect, until its entire habits and economy have been ascertained. Thus far, in the enquiry, is the strict province of the entomologist, whose attention ought, as it seems to me, to be directed, from day to day, and from year to year, not to isolated spots of ground, but to whole acres, more especially with reference to the peculiarities of seasons, and to atmospheric changes: but here we have only gone half way. way. It now becomes the province of the agriculturist to discover a remedy; since it seems equally clear that this ulterior branch of the enquiry can be prosecuted effectually only by persons perfectly conversant with the chemical nature of soils, the action of various ingredients which may be employed as remedies not only upon the insects themselves, but upon the plants which may be attacked. Such persons, too, are alone able to judge of the practicability of the application of the proposed remedies: since it is surely needless for an indoor entomologist to endeavour by experiment to discover remedies which, when discovered, cannot be adopted, either from the great expense of the article itself, or the impossibility of applying it; or the liability of the destruction, not only of the insect, but also of the plant itself; and even instances of the latter description have come under my own notice.

Hence it appears that the most efficient remedies will in all probability be suggested by those persons who, residing in the country, can obtain a knowledge of the economy of these destructive insects, founded upon the most general and prac

The bounding steed you pompously bestride,
Shares with his lord the pleasure and the pride.
Is thine alone the seed that strews the plain?
The birds of heaven shall vindicate their grain.
[Thine all the subjects of fair Flora's reign?
The insect races here their rights maintain.]
Thine the full harvest of the golden year?
Part pays, and justly, the deserving steer.
The hog that ploughs not, nor obeys thy call,
Lives on the labours of this lord of all."

Essay on Man, ep. iii. 27–42.]

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