Volume Ii Part 16 (1/2)
[Ill.u.s.tration]
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.