A rare species in Belgium, almost exclusively known from the southern provinces. Where both Theria species occur together, it is rarer than T. rupricapraria.

The larva lives on Crataegus or Prunus spinosa. Hibernates as a pupa underground.

The adults fly from January onwards till March and might be overlooked in some areas because of the early flight period. This species seems to fly a little earlier than T. rupicapraria. The adults come to light.

ID: Male; the forewings are almost unicolorous grey-brown; the central band does not contrast well with the ground colour; only the postdiscal line well indicated. Female; the forewings about 3/5 the length of the abdomen; the central band much broader and browner than in T. rupicapraria and not as sharply defined. Another distinguishing mark is that the central band doesn't get smaller towards the dorsum side.