Sometimes the central area of the fore wings is clouded with blackish from the front to the inner margin; such specimens are referable to ab. chrysanthemi, Hübn. (Plate [16], Figs. 1 typical, 2 ab.)
The caterpillar, which may be found in the summer months, is greenish white with zigzag olive markings, the lines on the back meeting in the middle of each ring, where there is a small pinkish blotch; head, pale yellowish, striped with brown on the face. It feeds on wild chamomile (Matricaria), stinking mayweed (Anthemis), and Pyrethrum (Plate [18], Fig. 1). The Rev. Miles Moss, writing his experience of this species at Rossall, near Fleetwood, Lancashire, notes that until half-grown the caterpillars live exposed, and are then found lying in a half-circle on the crowns of unexpanded flower heads. At this time they are green with dark and also white markings. He adds that caterpillars measuring about an inch in length when collected, were preparing for pupation a week later.
The moth is out in April and May, and has been captured even in July. When chrysalids are kept indoors, but not dry, the moths sometimes emerge in March, and occasionally in the earlier months of the year. A habit more or less general among the species of this genus is to remain in the chrysalis state for two or more winters; the present species has been known to emerge during March of the first, second, and third years following that in which the caterpillars were found.
Widely distributed over England and Wales, but apparently most frequent in the seaboard counties. In Scotland it occurs up to Perthshire, and it is found on various parts of the Irish coast.
The Cudweed (Cucullia gnaphalii).
Portraits of two specimens of this very local species, kindly lent by Mr. R. Adkin, will be found on Plate [13], Figs. 4 and 5.
The general coloration is usually silvery grey, but occasionally it inclines to yellowish. The moth has rarely been noted by day, and only one specimen seems to have been captured on the wing. Even caterpillars are by no means common in their best-known localities, and of those obtained after much labour a large proportion may frequently prove to have been the victims of parasitic flies.
The caterpillar is green, inclining to olive green, thickly freckled with pale yellow atoms; a purplish-brown stripe along the middle of the back and two faint purplish lines along the sides; a pale yellow line along the region of the black-edged spiracles, which are set in purplish-brown blotches. (Adapted from Buckler.)
Its food plant is golden-rod (Solidago) and it feeds at night and hides by day, low down on the stems or under the leaves: July to September. In confinement the caterpillars will eat garden aster and Michaelmas daisy.
The British haunts of the species are chiefly in Kent (Sevenoaks, Tunbridge Wells, etc.), and Sussex (Tilgate Forest, etc.); but according to Barrett it is also known from Hampshire, Surrey, and Essex. Abroad, the range extends through Central Europe to Southern Scandinavia, Livonia, Southern Russia, the Altai Mountains, Italy, and Armenia; but the species is nowhere plentiful.