Status Rare Immigrant.
This species and Lesser Broad-bordered Yellow Underwing, Noctua janthe were only separated as different species in 1991. First recorded in Britain by John Langmaid at Southsea, Hampshire, on 9 July 2001.
Specimens of N. janthina (Lanmaid’s) must meet all the critical points (size, shape and tone, underside of forewing and upperside of hindwing)
Hindwing - The black outer border of the hindwing is generally broad, and extends along the costa without a gap, giving the overall effect of a black hindwing with a yellow spot.
Forewing - The underside of the forewing should also be examined, janthe (Lesser Broad-bordered) showing a toothed outer edge to the black area that ends well before the outer edge of the wing. The outer edge of the black area in janthina (Langmaid’s) is usually smooth ending closer to the outer edge of the wing.
Please see comparative images here mothdissection.co.uk
Confirmation requires all critical features to be met and photographed, and if not 100% certain, dissection of the genitalia.
New for Norfolk in 2018, when a male, the first of two moths, were trapped at Eccles-on-Sea (11/07/18, Neil Bowman, Gen. Det. Jon Clifton)Verification Grade Comment: Specimens must be retained / photographed showing hindwing and underside of forewing for confirmation. | Determination by Genitalia Examination Required | |
Recorded in 2 (3%) of 74 10k Squares. First Recorded in 2018. Last Recorded in 2023. |