About Thera britannica (Turner, 1925)
Description: This species has a wingspan of approximately 30–36 mm (1.2–1.4 in). It is very similar to the grey pine carpet, but generally has richer markings and a greyer overall appearance. The ground colour of its forewing ranges from light grey to blackish grey. Within the median band, there are individual dark brown to reddish-brown patches that often have a distinct white border. Three or more of these patches are ovoid, located near the trailing edge of the wing. The median band is fluted and typically has a narrow white edge. The sub-terminal line is usually well marked. The spring brood of this species is overall brown rather than grey. Key features that distinguish this species from similar relatives include the white marginal line of the central band, the distinct sub-terminal line, and the dark grey-brown hindwings. It closely resembles Thera obeliscata; see Townsend et al. for further details. Distribution: This species is found from the British Isles and France, through central Europe, to the north of the Carpathian Mountains. Its range extends north into southern Scandinavia. In the south, there are isolated populations in the Pyrenees, Corsica, the Italian peninsula, the Carpathians, the mountains of Greece (including the Peloponnese), and Bulgaria. It is more common in the northern regions of the Alps than in southern areas of the mountain range. Outside of Europe, confirmed records exist from north-western and north-eastern Turkey, Transcaucasia, and the Caucasus.
