Thera cognata, the chestnut-coloured carpet or Durham juniper moth, is a moth of the Geometridae family. It is found in Europe, Asia Minor, the Caucasus and Transcaucasus. The wingspan is 26–30 mm. The forewings are reddish-brown. The median band and the basal field are darker in color and these dark fields are delimited with black and white cross lines. The hindwings are whitish. Thera cognata is easily distinguished from Thera variata by its strong purple-brown or red-brown gloss. Hindwing a little more glossy than in Thera obeliscata.The typical northern form is rather small and in general dark reddish. - geneata Feisth., the prevailing form in the Alps and in Transcaucasia, perhaps also in the Pyrenees, is larger, somewhat paler and with a less definite red tinge, the ground-colour bei