Description: Wingspan 46-50mm. Adults generally reddish brown with two dark cross-lines and a small discal spot towards the costal edge of the forewing. A variable species throughout its range in N. Ireland with some individuals appearing much darker and redder than others. Mid-September to late November, occasionally a little earlier depending on the season.

World Distribution: Across central Europe to Asia Minor.

Irish Distribution: Widespread and frequently encountered in the east. Much scarcer further west and north, apparently restricted to well-scattered localities in Fermanagh, Londonderry and north Antrim. It probably occurs more widely in these areas, highlighting the need for more fieldwork in the later months of the season.

Ecology: An autumnal species found in a variety of habitats especially heaths, bogs and woodland. Adults come frequently to light in reasonable numbers and are occasionally found during the day resting on the trunks of trees. The larvae can be found from late April to the end of June on a variety of trees including oak Quercus spp., birch Betula spp, willow Salix spp., Hawthorn Crataegus monogyna and Blackthorn Prunus spinosa. It overwinters as a larva.

Key Identification Features:

• Two distinct crosslines on forewings
• Small discal spot on all wings; hindwings pale whitish brown
• Males have large comb-like antennae

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

iNaturalist: Colotois pennaria at iNaturalist World Species Observations database.