CHAPTER XVIII

_BOMBYCES_

This tribe is an important one, inasmuch as it contains those few moths whose silk is of present or anticipated commercial value. Many of the British members, even, make silken cocoons of moderate compactness, but none of them yield a quantity and quality of silk to justify any attempt to utilise it in the arts.

There are more than a hundred British species in this group, and these represent no less than seventeen families, which exhibit a great variety in their general appearance and habits.

Family--NYCTEOLIDAE

_The Green Silver-lined_ (_Hylophila prasinana_)

This family, under the name of _Chloephoridae_, is included by some authors among the _Tortrices_ (page 298), which they somewhat resemble in habits. It contains only four species, of which we will take one example--the Green Silver-lined.

[Illustration: FIG. 108.--THE GREEN SILVER-LINED.]

The fore wings of this insect are pale green, with three oblique silvery white lines, the middle one of which is far more distinct than the other two. The hind wings are silvery white in the female, and yellow in the male. It flies in May, and is common in the wooded districts of the south-eastern counties.

The caterpillar is pale green, dotted and striped with yellow, and has a reddish transverse band on the second segment. It feeds on oak (_Quercus Robur_), birch (_Betula alba_), hazel (_Corylus_ _Avellana_), beech (_Fagus sylvatica_), and alder (_Alnus glutinosa_), from which trees it may be beaten in July and August.

Family--NOLIDAE

_The Short-cloaked Moth_ (_Nola cucullatella_)

We select this common moth as a representative of the small family _Nolidae_, which contains only five British species. These are all small insects. They are nocturnal in their habits, and may be found at rest on the trunks of trees during the daytime. The caterpillars are hairy, and undergo their metamorphoses within silken cocoons.

[Illustration: FIG. 109.--THE SHORT-CLOAKED MOTH.]

The fore wings of _Cucullatella_ are pearly grey, with a dark patch at the base, a triangular spot on the middle of the costal margin, and wavy lines beyond this, parallel with the hind margin. The hind wings are grey, and devoid of any markings.

The caterpillar is of a brownish colour, with a line of lighter patches down the back, and it is covered with little tufts of hair. It feeds on the blackthorn (_Prunus spinosa_), whitethorn (_Crataegus oxyacantha_), and also on plum trees in our gardens during the month of May. The moth is on the wing during June and July.

Family--LITHOSIIDAE

_The Muslin Moth_ (_Nudaria mundana_)

The family _Lithosiidae_ contains several small moths, distinguished from the other _Bombyces_ by the narrowness of their fore wings. When the insects are at rest, all the wings are wrapped closely round the body. They fly at dusk on summer evenings, but may be obtained during the daytime by beating the boughs of trees. If an open net be held under the boughs during this operation, the moths will generally feign death and allow themselves to fall into it when they are disturbed.

[Illustration: FIG. 110.--THE MUSLIN MOTH.]

Most of the larvae of this family feed on the lichens that cover walls and the bark of trees, and they conceal themselves so artfully among this peculiar vegetation that it is no easy matter to search them out; probably many still remain unknown to entomologists.

Our first example--the Muslin Moth--has light brownish-grey and semi transparent wings, the front pair of which have darker markings arranged as shown in the illustration. It is a common moth, and may be met with in July and August.

The caterpillar feeds on lichens in June. It is of a dull grey colour, with a yellow stripe down the back, and has numerous little tufts of light hair.

_The Common Footman_ (_Lithosia lurideola_)

The fore wings of this species are of a leaden grey, with a bright yellow costal stripe which dwindles to a point just before it reaches the tip. The hind wings are very pale yellow.

[Illustration: FIG. 111.--THE COMMON FOOTMAN.]

The larva is black, with a reddish line on each side just above the feet. It may be found during May and June among the lichens of oaks, blackthorns, and firs, especially in the woods of the south of England.

The perfect insect flies during July and August.

Family--EUCHELIIDAE

_The Cinnabar_ (_Euchelia Jacobaeae_)

The family _Eucheliidae_ contains only four British species, two of which must receive a share of our attention. The first of these is the Cinnabar Moth, which is common in all localities where its food plants--the groundsel (_Senecio vulgaris_) and the ragwort (_S. Jacobaea_)--abound.

[Illustration: FIG. 112.--THE LARVA OF JACOBAEAE.]

Its colours are so striking that a glance at its representation (fig. 1 of Plate X) will render a written description quite unnecessary.

The caterpillar is a very familiar and conspicuous object. Its colour is bright orange, broken by several broad black rings; and its body is thinly covered with hair. When fully grown (July or August) it descends to the ground, and there changes to a smooth and shining reddish-brown chrysalis.

The moth appears in June or early in July.

_The Scarlet Tiger_ (_Callimorpha Dominula_)

This is certainly one of the most beautiful of all our moths. Its fore wings are dark olive green, with a lovely metallic lustre, and boldly marked with large white and yellow spots. These spots are arranged generally like those in the illustration, but are subject to great variation. The hind wings are crimson, with large black patches, chiefly distributed near the hind margin. The thorax is black, with two white streaks; and the abdomen crimson, with a black line down the back.

[Illustration: FIG. 113.--THE SCARLET TIGER.]

This moth is a common one. It may be taken in June and July. I have seen it flying somewhat freely while the sun was still shining brightly.

The caterpillar is very dark lead colour, nearly black; and is covered with little wart-like projections, from each of which protrudes a short black hair. There is a broad yellow broken line down the back, and two others on the sides. It feeds on the hound's-tongue (_Cynoglossum officinale_) and many other low-growing plants, hybernates through the winter, and is fully grown in May. Like the other members of this family, it spins a light silken cocoon, in which the hairs from its body are interwoven.

Family--CHELONIIDAE

_The Wood Tiger_ (_Nemeophila Plantaginis_)

The _Cheloniidae_ are popularly known as the Tigers--a title suggested by the tiger-like colouring of some of the prominent species. They differ from the Scarlet Tiger and the other members of the _Eucheliidae_ in that the males have ciliated or fringed antennae. The larvae, too, are more densely covered with hair.

The Wood Tiger (fig. 2, Plate X) is a beautiful insect, somewhat variable in its markings, but so conspicuously coloured that our illustration cannot fail to lead to its identification. It may be found commonly among the undergrowth of our southern woods during May and June.

The caterpillar is dark brown or brownish black, covered with little hair-bearing warts. The hairs are long and black on the foremost and hind segments, but shorter and of a brown colour on the middle of the body. It issues from the egg in September, feeds for a week or two on the leaves of violets (_Viola canina_ and _V. odorata_), heartsease (_V. tricolor_), plantain (_Plantago_), or groundsel (_Senecio vulgaris_), and then hybernates till the following March. It is fully grown in May, and then spins a light cocoon, with which its hairs are interwoven, among the leaves of its food plant.

_The Tiger_ (_Arctia caia_)

This splendid moth is exceedingly variable in its colour and markings, but its usual appearance corresponds closely with that of the illustration on Plate X (fig. 3). In some specimens the cream colour almost entirely covers the fore wings, while in others all four of the wings are completely covered with shades of brown. This insect is probably known to all my readers, for it is abundant everywhere.

The larva is as well known as the perfect insect. It is a kind of universal feeder, partaking readily of almost every low-growing plant, with perhaps a special partiality for dead nettles (_Lamium album_ and _L. purpureum_). It feeds also on the lime tree (_Tilia vulgaris_), and is commonly met with on apple trees and on the various plants of our flower beds. The young caterpillar makes its appearance in the autumn, and hybernates after feeding for two or three weeks only. It is full grown in June, when it spins a silken cocoon, and changes to a shiny black chrysalis.

The ground colour of the larva is black, but it is covered all over with long hairs, those down the middle of the back being grey, and the others brown. This familiar larva is known popularly as the Woolly Bear.

_The Cream-spot Tiger_ (_Arctia villica_)

There is yet another Tiger--the Cream-spot--too beautiful and too common to be excluded from our list. It is represented on Plate X (fig. 4); and, like the others of its genus, is so boldly marked that mistaken identity is impossible.

It is a very sluggish moth, more often seen at rest than on the wing, and will suffer itself to be roughly handled without making any attempt to escape.

The caterpillar may be observed on sunny banks, generally feeding on chickweed (_Stellaria media_) but sometimes on various other low-growing weeds, including the dock and the dandelion. Its colour is black, with red head and legs, and its body is covered with long brown hairs. It commences to feed in the autumn, hybernates throughout the winter, and is full grown in May, towards the end of which month it changes to a black chrysalis within a light silken web.

The perfect insect appears in June.

_The Buff Ermine_ (_Spilosoma lubricipeda_)

The _Cheloniidae_ also include three moths that are popularly known as the Ermines, two of which--the Buff and the White--are exceedingly common, and are among the constant visitors to our gardens during June and July.

[Illustration: FIG. 114.--THE BUFF ERMINE.]

The Buff Ermine has all four wings of a buff or ochreous tint, and spotted with black as here represented.

The caterpillar is whitish, with a white line down the middle of the back, and its body is covered with long light brown hairs. It feeds on the dock (_Rumex_) and many other low-growing plants during August and September, and spends the winter in the chrysalis state, lying within a loose cocoon on the surface of the ground.

[Illustration: FIG. 115.--THE WHITE ERMINE.]

_The White Ermine_ (_Spilosoma Menthastri_)

In this species the wings are of a pale cream colour, and the dots of the fore wings are more uniformly distributed than in the last. Its habits and life history closely correspond with those of _Lubricipeda_, and its larva may be found feeding on the same plants.

This latter may be distinguished from the caterpillar of the last species by the dark brown or black colour of the body, and the presence of an orange line down the back. It is covered with long brown hairs.

Family--HEPIALIDAE

The five species which compose this family are known as the Swifts, a title which they have earned by their rather rapid flight. Their wings are narrow, and the antennae very short.

In the larval state they are long, naked and unsightly grubs, that live under the surface of the ground and feed on the roots of plants. The chrysalides are armed with short spines projecting from the segments.

_The Ghost Swift_ (_Hepialus Humuli_)

One of the commonest of these moths is the Ghost Swift, which may be seen in hundreds on waste places in the south of England during the month of June. The wings of the male are white, with a silky gloss, and a very narrow brown margin. The fore wings of the female are yellow, marked with irregular reddish lines. The hind wings are of a dull smoke colour.

[Illustration: FIG. 116.--THE GHOST SWIFT--FEMALE.]

The larva is pale yellow, with a brown head, and a brown horny plate on the front of the second segment. It feeds throughout the winter on the roots of numerous plants, including the dock, dandelion, burdock, white dead nettle, black horehound, and the hop.

_The Common Swift_ (_Hepialus lupulinus_)

The fore wings of the male of this species are brown, with a bent whitish streak, sometimes broken, passing from the base to the middle of the inner margin, and then to the apex. The hind wings are smoke coloured, with a light brownish fringe. The female is much less distinctly marked, and presents a rather dingy appearance.

[Illustration: FIG. 117.--THE COMMON SWIFT.]

The larva is dingy white, with brown horny plates on the second, third and fourth segments. It feeds on the roots of d