[Dunn and Parrack refer to Pennithera firmata as Thera firmata] There is some confusion in Robson's catalogue concerning the identity of this and other species of Thera. He recognised only two species as present in coniferous plantations, whereas in fact, there are three, T. firmata, T. obeliscata and T. variata. His ideas of their distribution must therefore be ignored. T. firmata can be mistaken for T. obeliscata and it is possible that workers using South as their means of identification could easily have done this by recording all reddish brown specimens as firmata and all greyish brown to dark fuscous specimens as obeliscata. Reddish-brown specimens of obellscata can be found and indeed are almost as common as those of firrnata. The difference between the two lies in the more acute angulation of the inner border of the central fascia of the forewing in firmata as compared with that in obeliscata, not in differences of colour alone. [...] firmata is widely distributed in pine plantations, but on present knowledge does not appear to be as common as its congenor T. obeliscata.