Description: Wingspan c 42mm. The upper side of the forewings are white apart from a dark grey to black apical spot. The underside of the hindwings are tinged green with grey markings on most Irish specimens. The tips of the antennae are brown underneath. Females are larger than males and have less pronounced markings. In N. Ireland single-brooded flying from May to mid July. Occasional specimens have been reliably reported in August. These are probably second brood specimens, which is normal occurrence in Europe but which appears to be a very rare event in N. Ireland.

World Distribution: The two wood whites are found in most of Europe apart from northernmost Scandinavia, in Asia Minor and east to western Siberia. Cryptic Wood White is found in Ireland but has not been found in Britain.

Irish Distribution: The exact distribution of both Wood Whites needs to be determined, but it appears that only one species, Cryptic Wood White Leptidea juvernica, is found in N. Ireland. The true L. sinapis is apparently confined to the Burren area of Co. Clare. The 'wood white' has been recorded from most of N. Ireland, most commonly in lowland parts of Armagh, Down and Fermanagh. It is much more local further north. Before 1950 the species was considered very rare and an increase was noted in the 1960's. This may have stopped or even reversed in recent years.

Ecology: More investigation is needed into to the ecology of Cryptic Wood White in Ireland and how it differs from the true Wood White Leptidea sinapsis. The wood whites are colonial species found in sheltered grassy sites at the margins of scrub and woodland. The principal larval foodplant is Meadow Vetchling Lathyrus pratensis, but there are records of it using Bush Vetch Vicia sepium and Bird's-foot trefoil Lotus corniculatus. Adults feed on any flowers available in the habitat and will also drink from puddles. The well-camouflaged larvae feed singly on the leaves of the foodplant. The overwintering stage is the pupa.

Key Identification Features:

• Rounded white wings with dark wingtips
• Underside of hindwing greenish with grey markings
• Separation of the two Wood Whites requires examination of genitalia

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

iNaturalist: Leptidea juvernica at iNaturalist World Species Observations database.