The Moths of the British Isles Volume Ii Part 16

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2 Pl. 41.

1. GRa.s.s EMERALD: _caterpillar_.

2. BLOTCHED EMERALD: _caterpillar_.

3. COMMON EMERALD: _caterpillar_.

{103} The moth is out in June and July, and may occasionally be beaten out of a hedge or bush, but is most frequently obtained late at night, when it is active on the wing, and is attracted by a brilliant light.

The species occurs in woods, on heaths and moors, and in fens, throughout the British Isles, except the most northern parts of Scotland and the isles.

Abroad, the range extends to Amurland and j.a.pan.

THE SMALL EMERALD (_Geometra vernaria_).

This species (Plate 40, Figs. 2 and 3) is smaller than the last mentioned, the green colour is of a softer tint, and the lines crossing the wings, two on the fore wings and one on the hind wings, are whitish, and not waved.

The caterpillar hatches from the egg in August, and after hibernation is to be found in May and June on Traveller's Joy or Old Man's Beard (_Clematis vitalba_). It is then green, with white dots arranged in lines along the back and sides; the head is deep reddish brown, and this, and also the first and last rings of the body, have raised points. Transformation to the greenish chrysalis is effected among the leaves, drawn together with silk.

(Plate 44, Figs. 3 and 3a.)

The moth flies in the evening in July and August, and in the daytime may be disturbed, by the application of the beating stick, from its retreats in hedges, etc., where the food plant flourishes. Found in most of the southern and eastern counties of England, most frequently on the chalk; its range extends to Worcesters.h.i.+re. Except that it has been recorded as a doubtful inhabitant of Ireland, the species does not appear to occur elsewhere in the British Isles. The distribution abroad extends to Amurland. {104}

THE BLOTCHED EMERALD (_Euchloris_ (_Comibaena_) _pustulata_).

When quite fresh, this moth (Plate 43, Fig. 1) is exceedingly pretty; the pale blotches vary a little in size, as also do the reddish marks upon them.

The caterpillar adorns itself with particles of its food as soon as it leaves the egg in July; after hibernation it uses the scales or husks of the oak buds for the same purpose. When stripped of its trappings it is found to be reddish brown in colour, with three slightly darker lines along the back; hooded bristles arising from raised brownish spots afford means for the attachment of the masquerading outfit, each moiety of which is covered with silk on one side before being placed in the required position.

When beating oaks for larvae in May and June, the contents of the umbrella or beating tray should not be too hastily thrown away, but allowed to remain therein for awhile, and closely watched for any movement among the litter. The spectacle of a cl.u.s.ter of oak bracts suddenly becoming active will certainly arouse curiosity, and on examination the cause of the commotion will frequently be found to be the caterpillar of this species.

(Plate 41, Fig. 2; after Auld.)

The moth is out in June and July, and flies at dusk in and around oak woods. In the daytime it may be jarred from its perch in oak trees, and once I found a specimen on a fence in the Esher district. It has been known to visit light, and examples of a September emergence have been recorded.

As a British species it only inhabits England, and it has been noted from Staffords.h.i.+re and Leicester, but seems to be rare in the midland counties generally. It is more frequently found in the southern and eastern counties.

Abroad, the range extends through Central Europe to Southern Sweden, S.

Russia, N. Asia Minor, and Andalusia. {105}

THE ESs.e.x EMERALD (_Euchloris smaragdaria_).

In some examples of this species (Plate 43, Figs. 2, 3) the green colour is brighter than in others, and very occasionally it is tinged with bluish; typically, there are white cross lines on the fore wings, but the inner one is not infrequently absent, and more rarely both are missing. The white central spot is very rarely absent, and the edges of the fore wings are yellowish.

The caterpillar feeds on the sea wormwood (_Artemisia maritima_), and adorns itself with fragments of its food plant in much the same manner as that of the species last referred to. Although obtained in the autumn in some numbers from its food plant, it seems to have been rarely met with in the spring after hibernation. It is, therefore, advisable to collect the caterpillars about September, and transfer them to plants of the garden _Artemisia abrotanum_, locally known as "Southernwood," "Old man," or "Lad's love," or, where available, wormwood (_A. absinthium_) will suit it admirably. Upon either of these plants the larvae will hibernate, feed up in the spring, and become full grown about May. The early stages are figured on Plate 42, larva and pupa from photos by Mr. H. Main.

The moth is out in June and early July, but it is rarely seen in the open, although over sixty years ago a few specimens were put up from among gra.s.s and netted at St. Osyth; in later years an example or two have been taken at Sheerness in Kent. Possibly, others may also have been captured in one or other of the insect's haunts, but records are silent on the matter.

Barrett mentions a specimen emerging in September, and the Rev. C. R. N.

Burrows notes that part of a brood of caterpillars reared from eggs, and fed on _A. absinthium_, attained the moth state during the autumn. So far as concerns {106} the British Isles it seems to be almost exclusively an inhabitant of the salterns, or sea marshes of Ess.e.x.

Abroad, the species occurs inland, and is not confined to the coast; its range extends eastwards to Siberia and Amurland.

THE SMALL GRa.s.s EMERALD (_Nemoria viridata_).

This species, represented on Plate 43, Figs. 5 and 6, is readily distinguished by its small size and the well-defined white cross line on each wing. In most examples there is a more or less distinct whitish inner line on the fore wings. Ab. _mathewi_, Bankes, has all the wings dusted with orange scales, more especially on the outer marginal areas. A few examples of this form were reared in 1905, with a number of normal specimens, from eggs laid by a female captured in South Devons.h.i.+re.

The caterpillar (figured from a skin on Plate 44, Fig. 1) is green, roughened with whitish points; a dusky line along the middle of the back, marked on the front and end rings, also between the rings, with purplish red. Head, and first ring of the body, notched, the points reddish; last ring of the body pointed. When at rest on a twig it a.s.sumes a rigid posture, and the legs are tightly drawn together. It feeds on heather, sallow, and birch, but the general experience appears to be that in captivity it thrives best on a diet of hawthorn, and is especially partial to the young shoots. It may be obtained in July and August, and the moth comes out in the following May or June. In 1905, Mr. A. J. Scollick reared some caterpillars from eggs laid June 2nd, and hatched June 16th; all duly pupated, and a moth came up on December 20th of that year. Four others appeared in January and February, 1906.

[Ill.u.s.tration]

2 Pl. 42.

1, 1a, 1b, 1c. LARGE EMERALD: _egg, caterpillars and chrysalis_.

2, 2a. ESs.e.x EMERALD: _eggs, caterpillar and chrysalis_.

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2 Pl. 43.

1. BLOTCHED EMERALD.

2, 3. ESs.e.x EMERALD.

4, 7. LITTLE EMERALD.

5, 6. SMALL GRa.s.s EMERALD.

8, 9. COMMON EMERALD.

{107} The Rev. F. E. Lowe states that in Guernsey the species occurs exclusively among furze on cliffs by the sea, and chiefly where the plant is cut down from time to time. In Britain it inhabits heaths and mosses, but is very local. It is found in the English counties of Hants (New Forest, etc.), Dorset (Poole Heath, etc.), Devon (Woodbury, Exeter district, etc.), Norfolk (Horning), Worcester (Malvern district, rare); also at Methop, Witherslack, and other localities in Westmoreland and c.u.mberland. Only doubtfully recorded from Scotland and Ireland.

Abroad, the range extends to Amurland, Corea, and China.

THE LITTLE EMERALD (_Iodis lactearia_).

The green tint in this species (Plate 43, Figs. 4 and 7) is even more unstable than in others of the group. When quite fresh the wings can often only be described as whitish with a delicate green tinge, but even when the greatest care is taken to preserve it, the colour is apt to fade.

The caterpillar (Plate 44, Fig. 2, from a coloured drawing by Mr. A. Sich) is long and thin, with two points on the edge of the first ring, and one on the last ring, of a bright green colour, paler between the rings; the spots along the back are reddish, as also is the whitish-fronted deeply notched head. It feeds on the leaves of various trees and bushes, such as birch, oak, hawthorn, sallow, etc. It may be obtained by beating or searching from August to September.

The moth is out in May and June, in some seasons later, and may be beaten out of hedges, as well as from trees in woods. Generally distributed, and often common, throughout England, Wales, and Ireland. In Scotland it is locally common in Clydesdale, and occurs in other southern parts of that country.

Abroad, the range extends to Amurland, Corea, China, and j.a.pan.

THE COMMON EMERALD (_Hemithea strigata_).

When freshly emerged from the chrysalis, this species (Plate 43, Figs. 8 and 9) is darkish green, but it soon fades to a greyish {108} tint. Easily distinguished by its shape, and by the chequered fringes. It is the _aestivaria_ of Hubner, and _thymiaria_ of Guenee. The long, thin, green caterpillar is ornamented with reddish brown, the V-shaped marks on rings 5 to 8 are sometimes whitish; head, deeply notched, brown; the first ring of the body is also notched. It hatches from the egg in August, when it is said to feed on mugwort (_Artemisia vulgaris_), and other low plants; after hibernation it feeds on the foliage of oak, birch, hawthorn, rose, etc., and attains full growth in May or June. In late June and in July the moth may be put up from the undergrowth in woods, or from bushes in well-timbered hedgerows bordering lanes and fields. Specimens so obtained are poor in colour as a rule, and it is well, therefore, to rear the species from the caterpillar. (Plate 41, Fig. 3; after Hofmann.) This remark applies to all "Emeralds."

The species is often common in the south and east of England, and along the western side, including Wales, up to Ches.h.i.+re and Lancas.h.i.+re, but it becomes local in Worcesters.h.i.+re and northwards. There are few records of it from Yorks.h.i.+re, and its occurrence in Durham, Northumberland, and Scotland is doubtful. In Ireland it appears to be widely distributed, but scarce.

The range abroad extends to Amurland, Corea, and j.a.pan.

[_Thalera fimbrialis_. A specimen of this Central European species (identified by the late Mr. C. G. Barrett) was taken on August 7, 1902, by Mr. C. Capper, from a blade of gra.s.s growing on a slope under Beachy Head, Suss.e.x. The species is somewhat similar in appearance to _H. strigata_, but is larger; the hind wings are notched above the angle on the outer margin; the fringes of all the wings are chequered with red, and the antennae of the male are bipectinated.] {109}

ACIDALIINae.

PURPLE-BORDERED GOLD (_Hyria muricata_).