Description: Wingspan 32-37mm. Males have reddish brown forewings with a darker cross-line. There is also a small discal spot towards the costal edge of the forewing. The hindwings are pale whitish brown with a tiny discal spot. Females are wingless. From the beginning of January to late March.

World Distribution: Across central Europe.

Irish Distribution: This is one of the few moths that fly during the winter months which no doubt means that it is under-recorded. The distribution map does not give a meaningful picture of the current status of this species, but rather reflects the distribution of home-based recorders.

Ecology: A species normally found in a variety of habitats including woodland rides and clearings, hedgerows and suburban gardens. Males are attracted to light and become active from dusk onwards. The females are wingless and rest on the stems of the foodplant. The larvae can be found in April and May on Hawthorn Crataegus monogyna and Blackthorn Prunus spinosa.

Key Identification Features:

• Brown coloured forewings; pale hindwings
• Small discal spot in centre of forewings
• Pale white hindwings
• Flight time
• Female wingless

Distribution Map from NBN: Theria primaria at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Theria primaria at iNaturalist World Species Observations database.