Geometridae

70.1271 Cryptic Fern Horisme radicaria (La Harpe, 1855)

Migrant / Overlooked Resident?

Similar species: Fern Horisme tersata is more rufous in colour, has a small discal dot in the forewing (which is rarely present in Cryptic Fern) and has paler cross-lines and a weaker apical streak. If Cryptic Fern is suspected where it has not previously been recorded the genitalia may need to be checked.

Forewing: 11 to 14mm

Habitats: Open woodland, calcareous downland scrub, hedgerows and gardens.

Habits: The moth is occasionally disturbed in the day. It flies from dusk and comes to light. The first British record was at New Romney, Kent on 22nd July 2007 and it is now breeding in Kent. It has since been recorded at Eastbourne, East Sussex on 22nd May 2019.

Foodplant: The larva feeds on Traveller's-joy and possibly cultivated Clematis spp. It pupates in the leaf litter or in the soil.