The Moths of the British Isles Volume Ii Part 15

{97} This species was first made known as an inhabitant of the British Isles by Doubleday, who described it as _Hypenodes humidalis_, in 1850, from specimens taken in Ireland by Weaver in 1848. In 1850 it was found plentifully on one of the Ches.h.i.+re moors; and Harrison, in _The Zoologist_ for 1851, writes: "From the middle of July up to the 8th of August, it might be seen any fine evening, between the hours of six and eight, flying on most of our swamps [Keswick] in plenty." He goes on to state that the moths were so common that he boxed forty in less than an hour, and could have secured as many dozens. At the present day the species is to be found on boggy heaths and moors in Surrey, Hamps.h.i.+re, Dorset, and from Somerset through Gloucesters.h.i.+re into Berks.h.i.+re, and thence northwards through Warwick and Staffords.h.i.+re to Ches.h.i.+re, Lancas.h.i.+re, and c.u.mberland. Barrett mentions Perths.h.i.+re as a Scottish locality, and Kane states that it is common at Killarney in Ireland. When this species and its allies receive more of the collector's attention they may probably be found in many localities from which there are no records at present.

The range abroad extends to Amurland.

BREPHIDae.

By some systematists this small group of moths is treated as a subfamily of the Geometridae. _Brephos_, however, which is typical of the family, does not seem to have any close affinities with the Noctuidae or with the Geometers, and is therefore better considered as apart from both those families. Meyrick includes _Brephos_ with _Aplasta_, _Erannis_, and _Baptria_, in his family Monocteniadae.

Only five species are known to inhabit the Palaearctic Region, and two of these occur in Britain.

THE ORANGE UNDERWING (_Brephos parthenias_).

The white markings of the fore wings vary a good deal in size; in some specimens, chiefly males, they are very small and confined to the front margin; in others, mainly females, they are much enlarged, and the central one is continued as a band across the wings. On the orange hind wings the blackish {98} central band is usually more or less complete, but sometimes it is nearly or quite absent above the blackish triangular patch on the inner margin. Occasionally, there is a yellow blotch at the a.n.a.l angle, and frequently another on the costal area. Still more rarely the whole ground colour is yellow. (Figured on Plate 38, Figs. 1 [male] and 2 [female].) The caterpillar is green, with six white lines along the back, and white stripes along the sides. When young it feeds on the catkins of birch, and afterwards on the foliage. April to early June. (Plate 39, Fig. 1.)

The moth is out in March and April, and on sunny days the males may be seen flying, generally pretty high up, on the lee side of the birch trees growing on heaths; also in open s.p.a.ces in or around birch woods. The females rest on the twigs, as also do the males when the sun is obscured.

Both s.e.xes have been found sitting on the ground in sunny glades.

The species is widely distributed over the southern and eastern counties, common in many parts; but its range extends through England to Durham, and it has been recorded from Wales. Although it does not seem to have been noted in Scotland south of Kincardines.h.i.+re, it occurs on the east to Moray.

Westmeath is the only Irish locality that has so far been mentioned.

Its distribution abroad extends to East Siberia and Amurland.

THE LIGHT ORANGE UNDERWING (_Brephos notha_).

Very similar to the last species, but rather smaller in size, and the fore wings are much less variegated. The antennae of the male of this species are bipectinated, whilst those of _parthenias_ are finely serrated. (Plate 38, Figs. 4 [male] and 5 [female].)

[Ill.u.s.tration]

2 Pl. 38.

1, 2. ORANGE UNDERWING.

3. THE REST HARROW.

4, 5. LIGHT ORANGE UNDERWING.

6-8. GRa.s.s EMERALD.

[Ill.u.s.tration]

2 Pl. 39.

1. ORANGE UNDERWING: _caterpillar_.

2, 2a. LIGHT ORANGE UNDERWING: _caterpillar and chrysalis_.

3. LESSER BELLE: _caterpillar_.

{99} The caterpillar feeds in May and June on aspen, eating the foliage and hiding between two leaves drawn together. The head is greenish or greenish-brown, with three conspicuous black spots. Body, green, olive-green, or reddish; line along middle of the back darker green edged with white; two thin white lines on each side, and a whitish stripe along the spiracles. When mature it burrows into decayed bark or wood (virgin cork in confinement), and before changing to a reddish-brown chrysalis, it spins a thin covering of silk and woody particles over the mouth of the chamber. The caterpillar and the chrysalis are shown on Plate 39, Figs. 2 and 2a. Although the bulk of the moths emerge the following April, some have been known to remain until the following or even the third year. The males fly about aspen, but only in the suns.h.i.+ne; in other respects its habits are pretty much those of the last species.

The distribution of the species in England seems confined to two areas: a western one represented by Worcester, Gloucester, with Monmouth, Wales, Wilts, and Dorset; and an eastern one by Norfolk, Cambridges.h.i.+re, Suffolk, Ess.e.x, Middles.e.x, Kent, Surrey, and Suss.e.x. In Scotland only recorded from Moray.

The range abroad extends to Amurland.

GEOMETRIDae.

Caterpillars of this family of moths, with very few exceptions, have only two pairs of claspers or prolegs; when there are more than four claspers, the extra ones are only rudimentary and therefore useless. In moving from place to place the caterpillar stretches out to its full length, first to one side and then to the other, as though measuring the distance. When a hold is secured with the true legs the body is arched and the claspers are brought up almost to the point held by the true legs; the latter are then thrust forward and the measuring business proceeds as before. Some kinds perform the looping manoeuvre very deliberately, but others at a quick rate. In common parlance among British entomologists the caterpillars are called {100} "geometers" or "loopers," but to our American confreres they are known as "measuring-worms" or "span-worms."

Most of the caterpillars feed openly on the foliage of trees, shrubs, or low-growing herbs, and the majority remain upon their respective plants during the day.

A large proportion of the moths may be obtained in the daytime, either by beating or otherwise disturbing the foliage or herbage among which they hide; several kinds rest on tree trunks, palings, rocks, walls, etc., where they are sometimes conspicuous, but more frequently not easy to distinguish from their surroundings. On the whole, members of this family are more available to the day collector than are those of the Noctuidae. Although several species occasionally visit the sugar patch, such species are, as a rule, obtained more readily and in larger numbers by other methods.

Brilliant light has a great attraction for many of the moths, some are more often captured at gas or electric lamps than in any other way, and among these are the migratory species.

Staudinger divides the family into the following subfamilies:--

Geometrinae (= Geometridae, Meyrick).

Acidaliinae (= Sterrhidae, Meyrick).

Larentiinae (= Hydriomenidae, Meyrick).

Orthostixinae (not represented in Britain).

Boarmiinae (= Selidosemidae, Meyrick).

Except as regards the Larentiinae, I have largely adhered to Staudinger's arrangement of genera in each of the above subfamilies.

The typical genus of Larentiinae would be _Larentia_, Treit, to which something over two hundred species are referred by Staudinger, among which are upwards of sixty that occur in the British Isles. Following some of the later generic changes, I find that none of our species are left in _Larentia_, but a few fall into _Hydriomena_, Hubner, and therefore Hydriomeninae has been adopted for this subfamily. {101}

GEOMETRINae.

THE REST HARROW (_Aplasta ononaria_).

This greyish-brown moth has two darker, sometimes reddish, cross lines on the fore wings, and one such line on the hind wings. It is presumably only to be regarded as an accidental visitor to England. The first record was of a specimen captured in the Warren at Folkestone in July, 1866, and since that year others were obtained in the same locality, but apparently not more than about half a dozen altogether. None seems to have been recorded for over thirty-five years. The specimen, whose portrait is shown on Plate 38, Fig. 3, was obtained from Dresden.

Abroad, the range includes Central and Southern Europe, Asia Minor, Syria, and Armenia.

THE GRa.s.s EMERALD (_Pseudoterpna pruinata_).

When freshly emerged from the chrysalis, the species represented by Figs. 6 to 8 on Plate 38 is of a beautiful blue-green colour, but in course of time a greyish shade creeps over the wings. The dark cross lines vary in intensity; in some specimens well defined and blackish, in others very faint, and hardly discernible; occasionally, the s.p.a.ce between the lines on the fore wings is dark shaded; the whitish submarginal line is not always present. This species is the _cythisaria_ of Schiffermiller, and the _cytisaria_ of other authors.

The caterpillar (figured on Plate 41, Fig. 1, from a coloured drawing by Mr. A. Sich) is green, with three lines along the back, the central one dark green, the others whitish; a pinkish stripe low down along the sides, the points on the head and the first and last rings of the body are often pink also. It feeds on pettywhin (_Genista anglica_), also on broom (_Cytisus scoparius_) {102} and gorse (_Ulex_); in captivity it seems to thrive on laburnum. Most frequently obtained in the springtime after hibernation.

The moth is to be found in June and July on moorlands and commons pretty well throughout the British Isles, but it seems not to have been noted north of Perths.h.i.+re, in Scotland.

Odd specimens have been known to occur in late August or early September, but this is quite exceptional.

THE LARGE EMERALD (_Geometra papilionaria_).

This charming green species (Plate 40, Figs. 1 and 4) varies in tint and in the distinctness of the whitish wavy cross lines. In some examples, one or other of the lines is absent, and far more rarely there is but little trace of any of these markings. Occasionally, the discal mark is preceded by a whitish wedge-shaped spot on the fore wings (ab. _cuneata_, Burrows).

When newly laid the eggs are whitish, but soon change to greenish yellow, and finally to pinkish.

The caterpillar hatches in late summer, and feeds on birch, hazel, and beech, until the leaves begin to fall in the autumn; it then constructs a carpet of silk on a twig, and near a bud, upon which it takes up its position for the winter. When thus seen, its reddish brown colour, variegated more or less with green, a.s.similates so closely with its surroundings that the creature is not easy to detect. In the spring, when it awakens, the green colour increases in extent as the buds open and the leaves unfold; when they are fully expanded, the caterpillar sits among the foliage towards the tip of a twig, and is then almost entirely green, the reddish brown only showing on the head, slightly on the warts, and more distinctly on the hinder parts which are in touch with the twig. The chrysalis, enclosed in a flimsy silken web among the dead leaves, usually on the ground, is of a delicate green colour, dotted with buff on the back, and shaded with buff on the wing cases. The early stages are figured on Plate 42.

[Ill.u.s.tration]

2 Pl. 40.

1, 4. LARGE EMERALD.

2, 3. SMALL EMERALD.