The green caterpillar, when full grown, is ornamented with brown-bordered reddish spots on the back, but these markings are absent in its earlier stages. The head is paler than the body, and has a reddish spot on each side. It feeds, in July and August, on sloe, plum, and bird cherry in this country, but the continental authors give birch, willow, rose, etc. The moth is out in May and June, and occurs throughout England and Wales, to Cumberland; but it is far more frequent in the south than in the north. Barrett mentions a single specimen from Wigtownshire in Scotland. In Ireland, Kane states that it is abundant at Clonbrock, Merlin Park, and in several other localities in Galway; it is not uncommon at Killarney, Kerry; and a few specimens have been taken at Powerscourt, Wicklow, and Sligo.
The range abroad extends to Amurland and Japan.
Common White Wave (Cabera pusaria).
In its typical form (Plate [107], Figs. 10, 11) this white species has three dark-grey almost parallel cross lines on the fore wings and two on the hind wings. The first or the second of these lines on the fore wings may be absent, occasionally both may be missing and the third very faint. Not infrequently in undersized bred specimens the first line approaches the second line either throughout its length or near the inner margin, and more rarely the two are united; in most of such aberrations the tips of the fore wings are rather more rounded than in typical specimens, and these are referable to ab. rotundaria, Haworth (Round-winged Wave). I have over a dozen examples of this form, all of which were reared from caterpillars which had been kept on short rations when nearly mature; in some, the outer margin of the fore wings is distinctly rounded, but in others it is much the same as in the larger typical form, and one of these is shown on Plate [107], Fig. 12. The ground colour occasionally assumes a greyish tint, and sometimes this is tinged with pink; more rarely the general colour is leaden grey.
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| 2 Pl. 106. |
| 1. | Barred Red: caterpillar. |
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| 2, 2a. | Barred Umber: egg, natural size and enlarged, and caterpillar. |
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| 3. | Light Emerald: eggs, natural size and enlarged. |
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| 2 Pl. 107. |
| 1-3. | Clouded Border. | 4, 5. | Scorched Carpet. | 6. | Sloe Carpet. |
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| 7, 8. | Clouded Silver. | 9. | White-pinion Spotted. |
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| 10-12. | Common White Wave. | 13, 14. | Common Wave. |
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The caterpillar, of which there are two broods, one in July and another in September, feeds on birch, alder, sallow, etc. It is purplish brown, spotted with white above, and greenish below on the first three rings. There is also a green form with purplish brown marks on the back. (Plate [105], Fig. 3, from a coloured drawing by Mr. A. Sich.) The moth is out in May, June, and August, and is generally common throughout the greater part of the British Isles.