great damage to young trees in our nurseries by eating the roots; and as they remain for several years in the larval state, it is difficult to get rid of them.

Fig. 322.

With regard to wireworms, Blandford (op. cit., p. 158) considers that"It is desirable to examine the ground selected for the nursery, and to reject the plot if it appears badly infested, or to cleanse it thoroughly before. planting. As the acreage required is small, there should be no difficulty in doing this by methods known and practised in agriculture, such as paring off and burning two inches of the top-soil early in autumn, or dressing with gas-lime, chloride of lime, or ammoniacal waste, and leaving it fallow till the effect of the poison has worn off. Fallow land kept clean and free from weeds during the period of egg-laying in June will have comparatively few wire-worms, but in the absence of better food these probably feed on humus, especially when young.

"If seedlings are actually attacked, handpicking is a good remedy when facilitated by the use of potatoes, carrots, or sliced mangold, laid on the ground as a bait and regularly visited. A dressing of rape-cake or mustard-cake, popular in hop-growing, may be tried, but the value of it under these circumstances remains to be proved. Serious injury from wire-worm is unlikely to extend beyond the first year of growth."

1:1

b

II. Moths and Butterflies (Lepidoptera).-There are large numbers of these interesting and beautiful insects which do great damage to trees of various sorts; but to enumerate all the species would take a whole volume by itself. Mention can only be made of a very few of them, therefore, or such as do most mischief to our forest-trees, and are generally to be found in our woods. This order of insects derives its name from a conspicuous peculiarity of their wings, the ordinary membrane of these being covered with a number of minute scales, placed like the tiles on a house-top. They are generally supplied with brilliant colours, which are situated in these scales.

The Processionary or Oak-Moth (Cnethocampa processionea), natural size.

a. Imago (male).

b. Caterpillar at work on an Oak-leaf. c. Pupa, seen from below.

1. The Processionary Moth (Cnethocampa processionea).—This moth (Fig. 322) is very injurious to the Oak, the larvæ constructing a nest upon the branches. They are hairy, with stripes and yellow spots upon the back, and are much similar to those common caterpillars seen upon fruit-trees, the perfect insect of which is called the

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VOL. II.

Lackey Moth (Gastropacha neustria). These insects live upon the leaves of the Oak, and are often found in considerable numbers upon. one tree. They derive their name from the fact of their proceeding in regular order, the one after the other, in search of food. To the same class belong the Hop-Dog (Dasychira pudibunda), the Browntail Moth (Porthesia chrysorrhea), the Gipsy Moth (Liparis dispar), and the Buff-tip Moth (Pygara bucephala), which destroy the leaves of several species of Hardwoods, also the Satin Moth (Liparis salicis), which does great damage, especially among Willows, as well as several others which feed on the leaves of Pines and Firs-the most important being Gastropacha pini and Liparis monacha.

The following extract from Kauschinger-Fürst (op. cit., p. 202), will illustrate some of the facts connected with the Processionary or Oak-moth :—

"It is only the Oak that is attacked by this insect; but as it occurs not infrequently, the injuries inflicted can assume considerable proportions. Trees in the full enjoyment of light and air are, on the whole, most exposed to attacks from the Processionary Moth, as, for instance, standard Oaks of all descriptions, and trees near the edges of compartments. When total denudation of the foliage takes place repeatedly, so that not infrequently the mid-summer flush of leaves is destroyed as well as the spring foliage, the results are often not merely confined to temporary loss of increment, but may induce a sickly condition of growth, with 'stag-headedness,' and may ultimately lead directly to the death of the tree.

"But another danger is threatened by the long, brittle hairs, which contain some substance poisonous to both man and beast, and produce swellings and inflammation where they happen to be brought in contact with the skin. When old Oaks growing on grazing land are attacked by the caterpillars, the hairs of the latter are often swallowed by the cattle when feeding, and may occasion them a good deal of suffering.

"Protected by these long poisonous hairs, the caterpillar has few natural enemies beyond the cuckoo, and a few Tachine and Ichneumonidæ ; but, on the other hand, the ova are well-nigh decimated during the winter by tomtits, woodpeckers, &c.

"The best annihilative measure that can be adopted against this insect consists in the removal and crushing or burning of the nests containing the caterpillars and chrysalides; when these latter are high up the stem, ladders will either be necessary, or else a pole with a knob of tow dipped in petroleum, and then lighted so as to set fire to the nest. For nests that are too high up for this method to be successful, Altum recommends the use of the gun with a large charge of very small shot and a small charge of gunpowder, so as to knock the nest to pieces.

"Whether the caterpillars be collected first or directly destroyed, the greatest caution should be taken to ensure that the woodmen should not have their health injured in any way by the poisonous hairs. Thick gloves, and an adequate protection, as, for instance, a damp sponge over both mouth and nostrils, are necessary; and if the exterminative measures can take place during wet weather, so much the better, as the hairs are not only less brittle then, but are also less apt to float about in the air.

"In areas infested for the time being by these caterpillars, the woods should, for obvious reasons, be closed to the collection of berries, the cutting of grass, and the herding of cattle."

The moths which are most injurious to coniferous woods in Germany include, among Spinners (Bombycida), the Pine-moth (Gastropacha Pini) and the Spruce-moth (Liparis monacha); among Owlet-moths (Noctuide), the Pine Beauty (Trachea piniperda); among Loopers (Geometrida), the Pine Span-worm (Fidonia piniaria); among Leaf-rollers (Tortricida), the Pine-shoot Tortrix (Retinia buoliana), the Pine-bud Tortrix (R. turionana), the Pine Resin-gall Tortrix (R. resinella), and the Spruce-shoot Tortrix (Grapholitha pactolana); and among LeafFig. 323. moths (Tineida), the Larch Mining-moth (Coleophora laricella).

2. Pine-Bud Tortrix (Retinia Turionana).---This moth is very injurious to the buds of Pine-trees, and threatens to be as great an enemy to the forester as the Pine-beetle. The following description is taken from Miss E. A. Ormerod's notes, already mentioned:

"This moth is somewhat under an inch in the expanse of the wings; the fore-wings bright orange, with several irregular or bifid transverse silvery streaks; the hind-wings dusky lead colour. The larva is glossy, of a dark purplish brown; the head, the transverse patch on the second segment, black. When full fed, it turns to pupa in the Pine-bud on which it has been feeding."

This species, as well as the others of its genus, does great mischief by laying its eggs in the buds of the Pines, so that when the caterpillar emerges it immediately begins to eat both the buds and the pith of the young shoots. It is not easily detected, and invariably does much harm before it can be noticed. This genus

a

d

The Oak-Leaf Roller (Tortrix viridana)-natural size.

a. Imago or fully developed moth. Caterpillar spinning itself down

b.

c.

by means of a gossamer-like fila

ment.

Rolled-up Oak-leaf in which the

attacks not only the Scots Pine, but the Austrian Pine, the Remarkable Pine, and some others. Among several species, the more common and injurious are Retinia Buoliana, R. resinella, and R. hercyniana, the habits of which are all similar to those of the one now described.

chrysalid stage is passed.

d. Chrysalis.

The only practical method of annihilation is to revise the thickets diligently in April and May, and to break off and destroy any buds that are seen to be infested with the larva.

3. The Oak Leaf-Roller (Tortrix viridana).--The caterpillar of this small green species of moth (Fig. 323) lives upon the leaves of

Oak-trees. It is thus described by Loudon :-"The moth varies in the expansion of its wings from 7 to 13 lines; the anterior wings are pale green, with a whitish margin in front, and the posterior wings brownish. . . . The caterpillar of this moth rolls up the Oak-leaves in a very ingenious manner, so as to form a very commodious retreat -in which, indeed, it ordinarily resides, the centre of the roll being open; its diameter is proportionable to that of the body of the insect, and the roll is secured by various little packets of silk attached to the Fig. 325.

body of the leaf, and to the adjoining part of the roll." In many cases the caterpillars strip Oak branches almost entirely of their foliage; they eat the leaves of the trees which they live upon in such a way as to do much injury to them, and to prevent them performing their natural functions in a normal and healthy manner.

"This moth swarms from about the middle till the end of June, when the female deposits her ova singly or in small clusters on the buds then being formed on the twigs in the crowns of Oaks. The tiny caterpillars make their appearance during the following spring, when they attack the buds, flowers, and foliage, and then about the beginning of June proceed to enter

the chrysalid stage in leaves rolled together, in fissures of the bark, &c., from which they emerge as imagines after a pupal rest of about three weeks; hence its generation is simple and annual.

"In consequence of the ova being deposited on the buds and young twigs, the feeding of the caterpillars always begins near the top of the leafy crown, and gradually works its way downwards, often resulting in total denudation of the foliage, which can only be replaced when the midsummer flush of leaves takes place." (Kauschinger-Fürst, op. cit., p. 211.)

4. The Larch-Mining Moth (Coleophora laricella) (Figs. 324, 325) is an insect closely allied to the Tortricidae, and, along with the Grey Larch-twister (Grapholitha pinicolana), is undoubtedly one of the predisposing causes to which a good deal of the Larch disease occasioned by the fungus Peziza Willkommii is attributable. So long as there are no wounds in the outer layer, cuticle, periderm, or epidermis of the foliage, shoots, and bark, fungoid spores coming in contact with plants, and germinating by throwing out their hyphee, can only develop normally when they are able to infect the plant by effecting an entrance into its living tissue, so as to find the requirements necessary to their growth as parasites. When once the foliage of Larch is damaged by hail, or by Coleophora laricella (which appeared in enormous swarms in some parts of Britain during the warm dry spring of 1893, and especially in Gloucestershire), or by Grapholitha pinicolana, or by the Larchbug or aphis (Chernies laricis), then the trees are not only predisposed to disease by the disturbance created within the organism, but doors are thereby opened for the entrance of the Peziza spores (see pp. 301, 304). Concerning the Larch-miner, Blandford (op. cit., p. 165) writes as follows:

"A special form of injury is that inflicted on Larch-needles by the larvæ of a tiny moth, Coleophora laricella, which lays its eggs at the end of June on the needles of the lower branches of Larches about 10 to 14 years old. The caterpillar mines into and feeds upon the interior of the needle, which becomes dry, yellow, and twisted; it then bites off the tip and detaches the needle about its middle, so as to form a tube in which it lives and passes the winter, concealed in a crack or under a bark-scale. In the spring it feeds on the new needles, and enlarges its tube by spinning a fresh needle along its side, biting it off and hollowing out the adjacent surfaces; in this tube it changes to a pupa, and ultimately to a moth. This insect is common in many English Larch plantations, whose foliage, when the attack is bad, has a dull withered look which is very conspicuous; it does not kill the tree, but keeps it year after year in an unhealthy condition.

"Practical treatment is difficult; picking off the injured shoots is very troublesome, and the only successful plan is to remove badly-attacked trees, and burn the foliage before the moth flies in June. It is best prevented by growing Larch in a suitable mixture, and not in pure woods. Special importance attaches to this and other Larch - feeding insects because the wounds which they make probably serve as a nidus for the spores of Larch canker."

5. The Goat-Moth (Cossus ligniperda).—This large moth (Fig. 326), which is commonly known by the name of " Augur-worm" in Scotland, is one of the worst of enemies to several species of broad-leaved trees. It attacks Elm, Oak, Willow, Poplar, Ash, Alder, Walnut, Beech, and Lime. The larvæ drill holes through the bark and into the timber, and finally cause a disturbance in the performance of the cambial duties.