The long caterpillar is bright green, with a darker green line along the back, merging into reddish on the last ring; sometimes reddish ochreous with the line along the back brownish. It feeds, in June and July, on larch, and will also eat spruce.
The moth is out in May and early June, and may be jarred from larch trees, or sometimes be found at rest on their stems.
As a British species, it was first met with in Surrey, in 1862, then it was noted in Sussex, and shortly afterwards in Yorkshire. At the present time, it will probably be found in any locality where larch is plentiful.
Grey Pug (Eupithecia castigata).
Although, as the English name suggests, this insect is greyish, there is always a tinge of ochreous in the composition of its general colour (Plate [97], Fig. 6). Not infrequently the ground colour is decidedly brownish in tint. The markings vary in clearness, but are most distinct in the paler forms. A blackish form occurs in the north of England, and in the Clydesdale district of Scotland, and was formerly known as the "Paisley Pug."
The longish caterpillar (Plate [92], Fig. 1) is pale or dusky olive, varying to reddish brown, with a series of darker marks on the back. It feeds, from August to October, on the foliage of almost any plant.
The moth is out in May and June, and occasionally a few specimens emerge in the autumn. Generally distributed over the British Isles, but apparently not noted in the Orkneys and Shetlands.
Abroad, the range extends to Amurland.