Volume Ii Part 18 (1/2)
As a British insect, it has only been known since 1851, when the capture of a specimen in the neighbourhood of Bristol was recorded in _The Zoologist_.
Subsequently it transpired that the scene of capture was Durdham Down, Gloucesters.h.i.+re, and here it has been found annually, and in some plenty, among the bushes and low vegetation covering the ground in that rugged locality. Specimens have also been noted from Berks.h.i.+re (Newbury), Bucks (Chalfont St. Peter), Dorset (Halstock), {117} and Norfolk (Thetford).
Possibly there are other localities in England, more especially in the west, where this species may be awaiting discovery.
THE SATIN WAVE (_Acidalia_ (_Ptychopoda_) _subsericeata_).
The wings of this species (Plate 45, Fig. 17) are glossy whitish, with a faint greyish, or sometimes yellow greyish, tinge; the cross lines are grey, oblique and straight on the fore wings, but the outer two on the hind wings are curved or bent.
Var. _mancuniata_, Knaggs, a local form found in Lancas.h.i.+re and Yorks.h.i.+re, is rather more tinged with yellowish, the lines being distinct, and some more or less distinct dusky dots on the outer margin of the fore wings.
A blackish form, with white fringes, has been recorded from North Cornwall, where the species, in its usual form, has been noted as abundant.
The rough-looking caterpillar is pale greyish, inclining to reddish above; three black lines along the back, the central one slender, and the outer ones widening out towards each end. It feeds on knotgra.s.s, dandelion, chickweed, and other kinds of weeds, and will eat plum. Hatching in August, it hibernates, as a rule, and attains full growth in the following spring; but sometimes caterpillars feed up quickly, and produce moths the same year.
The moth, which is out in June and July, is partial to heathy ground, but not confined to heaths, as it has been met with in lanes bordered by pasture fields. Widely distributed throughout England and Wales, rare in Scotland, where it has only been recorded from the Solway. In Ireland it has been found commonly at Howth, near Dublin; and in the counties Cork and Waterford. {118}
PORTLAND RIBBON WAVE (_Acidalia_ (_Ptychopoda_) _degeneraria_)
This reddish-banded species (Plate 46, Fig. 1) is, so far as we know, only found, in Britain, in the Isle of Portland, Dorset, where it was first noted on June 24th, 1831. It will be seen that apart from its different colour, the bands in this moth are placed nearer the base of the wings than in _A. aversata_; on the fore wings the band is limited by the first and central lines, but sometimes it encroaches on the basal area; on the hind wings, it occupies more or less of the basal area, from the first line inwards; the front edge of the fore wings is also reddish.
The caterpillar is ridged along the sides of the roughened body, and tapers towards the slightly notched, blackish marked head; the general colour is reddish-ochreous, darker on the back of the middle rings, along which are three interrupted pale greyish ochreous lines, and dark V-shaped marks. The natural food plant is not known, but it may be reared from the egg on bramble, traveller's joy (_Clematis_), and, of course, knotgra.s.s and dandelion, both of these plants being generally acceptable to larvae of the Acidaliinae, as well as to those of many other species of Geometridae.
The moth is out in June and July in the open, but has been bred as early as June 2. Some of the caterpillars from eggs laid in June will feed up quickly, and produce moths in September; from these, other eggs may be obtained, the caterpillars from which will feed for a time and then hibernate; as also do the slow-growing individuals of the earlier hatching.
Abroad, this seems to be a Mediterranean species, ranging eastward through Asia Minor to parts of Central Asia; and northwards to Austro-Hungary, Castile, France, and West Central Germany.
[Ill.u.s.tration]
2 Pl. 46.
1. PORTLAND RIBBON WAVE.
2. PLAIN WAVE.
3-6. RIBAND WAVE.
7-10. SMALL FAN-FOOTED WAVE.
9, 12. SINGLE-DOTTED WAVE.
8, 11. TREBLE BROWN-SPOT.
13, 14. LACE BORDER.
[Ill.u.s.tration]
2 Pl. 47.
1, 1a. SINGLE-DOTTED WAVE: _eggs and caterpillar_.
2. RIBAND WAVE: _caterpillar_.
3, 3a. PLAIN WAVE: _eggs, caterpillar and chrysalis_.
{119}
THE PLAIN WAVE (_Acidalia_ (_Ptychopoda_) _inornata_).
Somewhat similar to the last in appearance, but without reddish bands, and front edging to the fore wings; the second or outer line of the fore wings is generally distinct, but the others, especially the central, are often obscure. This species, one example of which is shown on Plate 46, Fig. 2, may be distinguished from the plain form of _A. aversata_ by its generally smaller size and more silky appearance; the cross lines are less distinct, and the outer one of the fore wings is not indented below the front margin.