CHAPTER XIX
_THE NOCTUae_
We have already noticed that several of our moths fly by day; that some come out of their hiding places at dusk, and settle down again to rest before the deepest shadows of night fall; and that others prefer the darkest hours of the night. The tribe of moths we are next to consider includes the greater number (about three hundred) of our truly nocturnal species, hence the name that heads this chapter.
They are generally of a somewhat dingy appearance, the prevailing colours being dull shades of grey, drab, and brown. So closely, in fact, do certain of them resemble each other, that the greatest care has to be exercised in the identification of species--a task that is rendered still more difficult by the variations that we observe in the tints and markings of certain species.
These moths have generally rather stout bodies. Their fore wings are somewhat narrow, and, when the insects are at rest, these are brought close to the body, and the hind pair are folded up beneath them.
Family--BRYOPHILIDae
_The Marbled Beauty_ (_Bryophila Perla_)
Our first family--the _Bryophilidae_--contains only four British species.
These are small and slender-bodied moths, whose larvae feed in early morning on the lichens that cover stones and old walls, and conceal themselves by day in holes and c.h.i.n.ks and under stones.
The Marbled Beauty is the only moth of this family that may be described as common with us. It is abundant in nearly every English county, as well as in parts of Scotland and Ireland.
[Ill.u.s.tration: FIG. 138.--THE MARBLED BEAUTY.]
Its wings are very pale grey, marked with a darker bluish grey, as shown in the engraving. These markings are variable, but the bases of the fore wings have always a dark blotch, followed by a patch of pale grey or white, extending the whole width of the wing. The moth may be found from the beginning of July to the middle of September.
The larva feeds from February to April. It is black above, with a broad orange-bordered stripe down the back; and its body is covered with small warts, each of which bears a single hair.
Family--BOMBYCOIDae
In this family there are sixteen British moths, several of which are exceedingly common. They are much larger than the _Bryophilidae_, and of a much stouter build. The larvae are covered with little hair-bearing warts, and are, indeed, often so hairy that they may be mistaken for the caterpillars of the _Bombyces_.
_The Grey Dagger_ (_Acronycta Psi_)
This is the commonest of all the _Bombycoidae_. It may be found at rest on tree trunks and palings during the daytime throughout the summer. Its fore wings are pale grey, with four conspicuous black marks, one of which--that in the a.n.a.l angle--resembles the Greek letter _psi_ ([psi]) placed sideways.
[Ill.u.s.tration: FIG. 139.--THE GREY DAGGER.]
The larva is black or very dark grey, with a pale yellow line down the back, and a black hump on each of the fifth and twelfth segments, that on the fifth being much larger than the other. It feeds in the autumn on lime (_Tilia vulgaris_), blackthorn (_Prunus spinosa_), whitethorn (_Crataegus oxyacantha_), fruit trees, and various other trees, shrubs, and herbs.
The moth called the Dark Dagger (_Tridens_) is hardly to be distinguished from _Psi_. It is not really any darker, and its markings are almost exactly similar; but the larva is very different.
_The Poplar Grey_ (_Acronycta megacephala_)
This is also a very common moth, to be found in all the southern and midland counties, wherever poplars abound, during June and July.
[Ill.u.s.tration: FIG. 140.--THE POPLAR GREY.]
Its fore wings are grey, marbled with a very dark grey. A little inside the middle of these wings, near the costa, is a round spot with a dark centre. This spot is represented in a large number of the _Noctuae_, and is known as the _orbicular_. It will be observed that in the present species it is very distinct.
The caterpillar is dark grey, with a line of black dots down the back; and it has a number of little warts, bearing hairs. On the back of the eleventh segment is a rather large pale spot. It feeds during August on various species of poplar, and changes to a chrysalis in a crevice of the bark.
_The Figure of Eight_ (_Diloba caeruleocephala_)
The fore wings are brownish grey. Near the middle of the wing, but nearer the costa than the inner margin, are two whitish spots that resemble the figure 8. The hind wings are dull brownish grey, with darker wing rays, and a dark spot near the centre.
[Ill.u.s.tration: FIG. 141.--THE FIGURE OF EIGHT.]
This moth is common in all parts, and flies during September.
The caterpillar emerges from the egg in spring, and is fully grown in May or June. It is of a very pale colour--yellowish or greenish--with a broad and broken yellow stripe down the back, and a bluish or greenish stripe on each side. Its head is blue (hence the specific name) with two black spots. It feeds on the hawthorn (_Crataegus oxyacantha_) and various fruit trees; and on the twigs of these (especially the hawthorn) the little cl.u.s.ters of eggs may be seen during the winter.
Family--LEUCANIIDae
In this family we have a number of rather small moths, with, generally, no markings on their wings, save, perhaps, a few dots or streaks.
Their larvae feed princ.i.p.ally on gra.s.ses and reeds, and change to the chrysalis state either in a coc.o.o.n among the food plants, or under the surface of the ground.
Several of these insects are very common, and most of them abound in fens and marshes.
_The Brown-line Bright-eye_ (_Leucania conigera_)
The fore wings are yellowish brown. The "brown line" is a transverse line parallel with the hind margin, and distant from it about one-fourth the length of the wing. Another dark brown line, describing a sharp bend, pa.s.ses across the wing near the base. The "bright eye" is a light spot just outside the centre of the wing, nearer the costa than the inner margin. This is another of those marks that occur very constantly in the wings of the _Noctuae_. It lies beyond the _orbicular_ spot, and is usually somewhat kidney-shaped, and is consequently named the _reniform_.
[Ill.u.s.tration: FIG. 142.--THE BROWN-LINE BRIGHT-EYE.]
The caterpillar is yellowish or greyish, with a pale dorsal line edged with black. On each side of this is a broad black line, below which is a yellow line edged with black, then a whitish stripe, next a yellow line edged with black on the upper side, and lastly a broad brownish line, just above the spiracles, edged with black on both sides. It feeds on couch gra.s.s (_Agropyron repens_) and various other gra.s.ses, and is fully grown in May.
The moth flies in July and August, and is common throughout the United Kingdom.
_The Smoky Wainscot_ (_Leucania impura_)
This same genus includes a number of moths, very similar in general appearance, and popularly known as the "Wainscots." Of these we shall take two examples.
The first is the Smoky Wainscot, so called from the dark smoky tint of the hind wings. Its fore wings are wainscot brown, with lighter rays; and they each have three black dots arranged in the form of a triangle, one in the centre, and the other two between this and the hind margin.
[Ill.u.s.tration: FIG. 143.--THE SMOKY WAINSCOT.]
The caterpillar is yellowish, with a fine white line down the back. The spiracles are red, and inclosed in black rings. It feeds on sedges (_Carex_) from March to May.
The moth is on the wing from June to August.