Its fore wings are pale brown crossed by a broad central bar, the edges of which are darker. The hind wings are of a paler brown, and are crossed by two or three fine wavy lines.
Although the perfect insect is so common, the caterpillar seems to be seldom met with. It is a grass feeder, and may be looked for in May and June.
The Treble Bar (Anaitis plagiata)
Our last example of the Geometræ is the Treble Bar, a very pretty moth, which is illustrated in fig. 9 of Plate XII. It may be readily identified by the aid of this coloured picture, and therefore need not be described in words. It is pretty generally distributed throughout the British Isles, and is in some parts a very abundant species, particularly so in the neighbourhood of London.
The caterpillar is brown, with paler spaces between the segments. The dorsal line is black and interrupted, and a yellow line runs along each side. It feeds on the leaves and flowers of the perforated St. John's wort (Hypericum perforatum).
This insect is double brooded, the moth appearing in May and August, and remaining with us throughout the month following in each case.