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lays 300 to 400 brownish-grey eggs in a close spiral band round twigs and small branches, chiefly of fruit-trees and Oaks, but also on Elm, Hornbeam, Poplars, and Willows. The young caterpillars hatch out towards the end of April or early in May, and at once begin to feed on buds and leaves. They live in communities inside "tents' or nests until fullgrown. About the end of June they break up their colonies, and pupate singly between leaves or in bark-fissures, by attaching themselves to these with a few loosely spun threads.
Protective and Exterminative Measures.-As for the Brown-tail Moth.
4. The Black Arches, "Nun," or Spruce Moth, Bombyx (Liparis) monacha. -In Central Europe this is one of the most destructive pests in Spruce and Pine woods, but in Britain damage to any considerable extent has never yet been recorded. It is usually only to be found on broad-leaved trees (especially Oak) in the warmer parts of England.
Appearance. When extended, the wings of the female moth have a span of about 1 to 2 inches. The smaller male is easily distinguishable by its double-combed antennæ. In both the outer wings and the upper part of the body the ground-colour is white, marked with numerous deeply-arched, zigzag, brownish-black or black stripes (hence the name "Nun," from the plain black-and-white colouring); the lower wings are brown-grey, edged with black spots. The abdomen, though sometimes blackish, is mostly rose-colour, with black transverse bands; but melanic (black) sports are not uncommon.
The caterpillar, about 14 inch long when full-grown, is whitish- to reddish-grey on the upper side and dirty-green on the lower. It has a broad grey dorsal stripe, commencing from a black heart-shaped patch on the second segment of the body, but narrowing and interrupted by a broad light patch on the seventh and eighth segments. Each segment has six small tubercular hairy warts, of which the two first, on the first segment, rise above the others, whilst those on the other segments, to the right and left of the dorsal stripe, are blue. These form a constant characteristic of this caterpillar, however much it may vary in general colour.
The densely-haired pupa, at first greenish, then turning a bronzy-brown, lies in a flimsy cocoon, formed of a few dirty yellow threads spun between bark-fissures on the lower part of the stem, among foliage on branches and twigs, or on underwood and brushwood.
Life-history.-The moths fly late in July or early in August. In the daytime especially during dull weather, they swarm low down on the stem, whilst during bright sunshine they are restless, the males in particular keeping flitting about. But, like most other moths, their habit is mainly nocturnal.
The female moth lays her eggs on or beneath bark-scales, or under some such protection as lichens. The eggs are at first of a bronzy rose-red, but afterwards turn greyishbrown with mother-of-pearl lustre. When the insect is not in large numbers, the eggs are usually laid on the lower part of the stem within 15 feet of the ground; but during great devastations (such as that which occurred in the Spruce tracts of Bavaria and Western Austria in 1889-91, the fight against which cost £100,000, and the sacrifice of many millions of trees) they cover the whole of the stems from top to bottom. One female can lay from 150 to 170 ova, mostly in clusters of 20 to 50, though sometimes all are deposited in one patch.
Although the larva becomes fully formed in four weeks, yet it hibernates within the shell, and only hatches out in the following April or May. The young caterpillars remain for several days in clusters, the blackish caterpillars often showing up plainly against the brown Spruce bark. After about four to six days these colonies scatter, and the young caterpillars ascend to feed on the foliage. They first attack the lower branches, then gradually work upwards, clearing the branches and twigs of needles. Spruce foliage they devour entirely, but on the Pine they bite through the needle about half-way up, and eat only the remaining lower part. When they attack broad-leaved trees, they gnaw through the mid-rib, so that the top part of the leaf falls to the ground, which is often covered with the top parts of needles and leaves during bad attacks.
The caterpillars moult their skin four times, and until about half-grown they spin
gossamer threads to let themselves down to the ground. They feed till late in June or early in July, when they descend in masses from the stems to pupate under bark-scales, or on the undergrowth, &c.
Preventive and Exterminative Measures.-One can hardly prevent this moth from appearing now and again. But as soon as its presence is discovered annihilative measures are now in Germany promptly taken to exterminate the brood and obviate serious damage. Constant careful inspection of the woods should discover the presence of the characteristic fragments of bitten leaves and needles scattered about the ground, while the gradual thinning of the foliage, and later on the moths themselves, will show when exterminative measures are called for (see Figs. 137 to 141, pp. 67-70).
The eggs may be collected from August till April, if merely laid near the base of the stem, when the egg-clusters can be scraped off with a knife into a bag. But many eggclusters are sure to get overlooked (especially on the thick-barked Pine), so that this method can at best only prove partially effective. It is perhaps easier to crush the little colonies of caterpillars whilst collected together for four to six days just after hatching out. While thus clustered near the foot of the stem, they are easily killed with a leather flap tied to the end of a stick; but even this is also at best only partially effective.
There are few natural enemies of this moth, and especially of the hairy caterpillar. Many kinds of birds (tomtits, &c.) feed on the eggs in winter, and useful insects (Ichneumonida and Tachinine) prey on the caterpillars. This moth is comparatively insensible to changeable weather and climatic influences. Its ravages usually cease after the third year, when the caterpillars become degenerate and die off in large numbers.
During the Bavarian and Western Austrian calamity, after various remedies had been tried during 1889-90 (including experiments made with exhaustors working close behind strong electric lights), a young forester named Mayer suggested trying grease-banding with rings of patent tar round all the stems in a young 12- to 15-year-old Spruce plantation cleared of all lower branches for this purpose. This proving successful, it was continued on a larger scale in 1891, and all stems, from the thickness of a finger upwards, were ringed with patent tar wherever it was known that the moth was present. Millions of stems were thus ringed at breast-height, as this is much less expensive than, and quite as effective as, ringing at 15 to 18 feet above ground, because the success of this measure is due to the fact that nearly all the caterpillars spin down on threads from the treecrowns to the ground before they lose this spinning-power, and when they reascend the trunks, they are prevented by the viscous band of tar, whose smell or taste or touch they abhor; and being thus unable to ascend, they starve and die of hunger below the rings.
Other Spinner-moths, all of them also of minor importance in British woodlands, include the following three species :
5. The Common Vapourer Moth, Bombyx (Orgyia) antiqua, with a wing-span of 1 to 14 inch. The male is rusty-brown, with two dark transverse bands and a white moon-spot on each fore-wing; the female is yellowish-grey, with wings aborted into white stumps. The caterpillar is ashy-grey with yellowish hairs, a velvety-black back and carmine warts; it has two long black tufts of hair behind its head, other two projecting at right angles to the sides on the fifth segment, and one standing erect on the eleventh segment. It flies in August and September, and lays from 150 to 300 eggs on the nest from which it has emerged. The larvæ occasionally hatch out in autumn, but mostly not until spring. It chiefly attacks buds, foliage, and young fruit in orchards, but is also found on Willow, Mountain-Ash, Spruce, and Scots Pine. It pupates in June or July, the pupation lasting about six weeks.
6. The Satin Moth, Bombyx (Liparis, Leucoma) salicis, has a wing-span of 2 to nearly 2 inches. The wings are white and lustrous, and the legs are ringed with black and white. The caterpillar is 13 inch long, and grey, with yellowish-white dorsal spots, small red warts, and light-brown hairs. The female lays 150 to 200 eggs in June and July on the bark or leaves of Poplars and Willows, and covers them with a white membrane. The caterpillars sometimes hatch out in autumn, but mostly not until the following spring, when they feed on the foliage until they pupate about the end of May loosely attached to leaves or twigs.
7. The Gold-tail Moth, Bombyx (Liparis, Porthesia) auriflua, lives chiefly on fruittrees, but also on Oak, Beech, Elm, Birch, Lime, Willows, and various shrubs. It has a wing-span of 1 to 12 inch, and much resembles the Brown-tail Moth; but its body is of a lighter golden colour, and the inside edge of the wings has a longer fringe. In June and July it lays 150 to 200 eggs in clusters on foliage, and covers them with golden-yellow fluff from its tail. The caterpillars hatch out in August. They are black, with blackish-grey hairs, two vermilion dorsal lines, and patches of white hairs. They feed on leaves, buds, flowers, and young fruit, hibernate on the ground or in bark-fissures near the ground, and recommence feeding in the following spring till they pupate, about the end of May or in June, in rolled-up leaves or on twigs. The pupa is blackish-brown, and enclosed in a thin whitish-brown cocoon.-Grease-banding with patent tar in early spring is recommended.
B. Owlet-Moths or Night-Moths (Noctuidae).
Moths with narrow wings, the fore-pair usually characteristically marked with transverse lines and spots; body thick and generally downy; antennæ long, fine, and fringed, but sometimes pectinate in male. They seldom fly during the day, but mostly in the twilight and the dark. Eggs round and dull in colour. Caterpillars (destructive species in woodlands) with 16 legs, and seldom hairy. Pupa usually dark in colour, thin, and spindle-shaped; pupation either without a cocoon, or else with one formed of a few threads. Generation annual.
1. The Pine Beauty or Owlet-Moth, Noctua (Trachea, Panolis) piniperda.-The Pine Owlet-moth or Pine Beauty, common throughout Britain, lives mostly on Pines (rarely on Spruce) and especially in pole-woods of 20 to 40 years of age. But when its increase is favoured by warm dry weather it is very prolific, and may become a very serious pest, doing considerable damage over large areas, and sometimes totally destroying Pine pole-plantations.
Appearance. The male and female moths are about the same size and are somewhat similarly marked; but the antennæ of the male are more feathered, and the abdomen of the female is rather thicker. The fore-wings and upper part of body are brown-red spotted with white or marbled with grey, and the large lower spot on each wing forms a crescent pointing downwards when the moth is at rest; the hind wings and abdomen are of a dark-grey brown, the wings having a lighter edge. The moth is bluish-red beneath, merging into blackish-grey near the base of the fore-wings, and into a black point on the hind-wings. Melanic and other sports are fairly common. The wing-span is about 1 inches.
The 16-legged caterpillar is fully 14 inch long when full-grown. It is yellowishgreen, with three to five whitish longitudinal stripes, and a yellow or orange stripe on each side just above the spiracles and the legs; and it has very few hairs Its head varies from light-brown to dark. As the two first abdominal legs are malformed, it moves somewhat like a span-worm, and while young the caterpillar can also spin gossamer threads freely.
The pupa is from to about of an inch long, greenish at first, but afterwards turning dark-brown, and with two hooked processes at its tail-end.
Life-history. The moth flies from about the end of March or early in April until the beginning of May. After pairing at night, high up in the trees, the female lays from 30 to 70 round green eggs, for the most part singly, on the needles of Scots Pine-poles and older trees (less frequently on Spruce and Weymouth Pine), pole-woods of 20 to 40 years of age being chiefly selected for ovideposition. When the caterpillars hatch out in May, they at once begin to gnaw the sides of the needles, but as they grow and become stronger, they eat the whole of the needle right down to the sheath. Towards the end of July or early in August, the caterpillars descend from the trees and pupate under moss and dead
foliage, or in loose earth and stump-holes, or on the ground, scattering themselves over the whole area attacked. They hibernate as pupa and emerge as moths in the following spring, the pupal rest extending over the exceptionally long period of about eight months.
Preventive and Exterminative Measures.-The Pine Beauty has many natural enemies, which devour the almost hairless caterpillar and the pupæ lying unprotected on the ground for about eight months. These include all insectivorous birds, predatory insects (Carabida), flies (Tachinina), and ichneumon-flies (Ichneumonida), also swine, hedgehog, and mice. Raw, damp, cold weather often kills the caterpillars quickly. Fungous disease (due to species of Empusa) also soon break out epidemically among them and terminate their attacks.
When pole-woods are infested, the caterpillars can easily be shaken off the young poles; or if the stems are too large for that, they can be tapped with a padded mallet or axe-head. They can also often be collected and killed in large numbers when they have finished feeding on the foliage and come down from the trees to pupate, because they often cluster together at the foot of the tree before hibernating as pupa. Herding swine in the woods is also useful, because they hunt and devour the pupa. Digging a trench round a plantation attacked is not of much use, as the caterpillars are not migratory.
C. Loopers or Span-Worms (Geometrida).
Moths with slim bodies; usually fly in twilight or dark; wings large and broad; antennæ filiform or silky and brush-like, and sometimes pectinate in male. Caterpillars with 10 (sometimes 12) feet, bare or only slightly haired, and progressing with an arched or "loop-like" movement (whence their name). Pupa long, brown, with a short pointed tail; pupation generally on the ground or under moss, leaves, &c., and not enclosed in any cocoon. Generation annual.
1. The Winter Moth or Winter Span-worm, Geometra (Cheimatobia) brumata. This moth, common throughout England, is often very injurious to orchard trees (and especially to Apple-, Pear-, and Plum-trees), but also attacks most kinds of broadleaved trees, being oftenest found on Oak, Elm, Hornbeam, and Lime (Fig. 159).
Winter Moth (natural sise).
A. Male. B. Female. c. Caterpillar.
Appearance. The male moth has a wing-span of about 1 to 1 inch, with fore-wings of a reddish- or yellowish-grey or grey-brown, marked with dark wavy transverse lines; the hind-wings are lighter, and marked with a faint dark stripe. The female is about of an inch long, greyishbrown, with white scales, long antennæ and legs, and only abortive rudimentary wings, so that it cannot fly.
The 10-footed caterpillar feeds on foliage till full-grown. Grey at first, it changes after the first moult of the skin to yellowish-green, with a green head and a pale dorsal stripe; but later on, when full-grown, it is about 1 inch long and green with a dark dorsal stripe, three narrow white lines along each side, and a brown head.
The pupa is light-brown, with two hook-like processes at the tail-end. pupates in a very loose flimsy cocoon.
Life-history. The moth flies from October till December (hence its name), when the males flit about towards dusk in search of the females, crawling up and down the trunks of the trees. After pairing the female lays from 200 to 300 eggs
(greenish at first and reddish later on), either singly or in very small clusters, on buds, leaf-scars, and twig-points in the crowns of broad-leaved trees.
The caterpillars hatch out in April and May, and feed on leaf- and floweringbuds before attacking the foliage, which they twist in much the same way as leafroller moths. Early in June they spin themselves down by gossamer threads to the ground, and pupate in sheltered places or in smooth holes formed about 2 to 3 in. below the ground. The moths mostly emerge in autumn (simple annual generation), though stragglers often hibernate as pupa and only appear in the following spring.
Preventive and Exterminative Measures, which are only really practicable in orchards, consist of spraying with poisonous washes (see Brown-tail Moth) or grease-banding with patent tar, or strips of stiff paper can be smeared with the viscous tar or with cart-grease and tied firmly round the stems (renewed in spring, if necessary) to prevent the abortive-wing females from crawling up the stems to the tree-crowns. The soil in orchards may also be dug to bury the pupa deep in the ground, and thus prevent their emerging.
2. The Pine Geometer or Bordered White Moth, or Pine Span-worm, Geometra (Fidonia) piniaria.1—This is a common moth in the coniferous localities of Britain. It usually attacks 25- to 40-year-old pole-woods of Scots Pine, and occasionally also of Weymouth Pine, Spruce, and Silver Fir. It is not here a very destructive insect, and the danger from its attacks is diminished by these only taking place after the Pine-leaves are fully developed and the buds for the next year's foliage have been formed (Fig. 160).
Appearance. The male and female differ little in size, the wings (which are borne upright while at rest) when extended having a span of from 1 to 13 inch. But they vary greatly in colour. The female has rusty-brown wings (both pairs), with paler edging. Two faint dark-brown transverse stripes run across the lower pair of wings, and one across the upper pair. The lower edges of both wing-pairs have a row of alternate light and dark spots. The yellowish antennæ are bristle-shaped. The ground-colour of the wings of the male is white (in Scotland) or yellowishwhite (in England), with a large triangular dark-brown patch at the apex of the fore-wings, and with broad dark-brown edging and transverse stripes, while the fringes of both wing-pairs are tipped with alternate brown and yellow spots. The large feathery antennæ are dark and double-combed.
The under side of the wings, similar in both genders, is of reddish-brown, with dark transverse lines (fainter in the female), a broad yellowish-white longitudinal stripe, and many small brown and white spots.
The yellowish-green 10-footed caterpillar is at first about inch long, and increases to 1 or 14 inch when full-grown. A white line runs along the middle of the back, with two parallel dark-green lines farther down on either side, and a paleyellow line close below the brown spiracles. All these lines extend to the green head, where the dorsal middle line forms a V mark. On the lower or ventral side there are three yellowish longitudinal stripes. Of the 10 feet, 3 pairs are thoracic, and 2 pairs are after-feet (one of these last 2 pairs forming the anal claspers).
The pupa (which much resembles, but is smaller than, that of the Pine Beauty) varies from about to an inch in length, and is at first greenish, but gradually changes to dark-brown.
Life-history. The moths (which live for about a fortnight) fly late in May and throughout June, when the males flit about in the daytime, although like
1 A monograph on this moth will be found in the Trans. High, and Agri. Socy. Scot., vol. ix., 1897, pp. 106-123.