LASIOCAMPIDAE | Lasiocampinae | Lasiocampini

66.006 Lasiocampa trifolii (Grass Eggar & Pale Grass Eggar)

ws: 40-55mm (UKMoths), fw: m21-24mm, f25-30mm (Waring & Townsend); Aug-Sep; lfp varies with subspecies and location.
ssp trifolii (Grass Eggar): NS-A sand-dunes on Isles of Scilly, Dorset (marram), Hampshire (tree lupin), Somerset, Glamorgan, Cheshire & Lancashire (creeping willow); sea-cliffs os S.Devon (bramble) and Cornwall; inland heathland in Dorset
​ssp flava (Pale Grass Eggar): RDB coastal shingle at Dungeness, Kent (false oat-grass)
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Lasiocampa trifolii trifolii (Grass Eggar) §2 male
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Lasiocampa trifolii flava (Pale Grass Eggar) §1 male
ID: The subspecies differ in ground colour - ssp trifolii ranges from reddish-brown to blackish-brown, ssp flava is straw yellow to brownish-yellow; a curved postmedian line meets the costa closer to the apex than the discal spot (the less curved postemedian line of Lasiocampa quercus (Oak Eggar) meets the costa closer to the discal spot than the apex); a curved antemedian line is variably expressed; a large dark-ringed white discal spot between the two lines. Distal to the postmedian line the ground colour is usuallt a shade paler. in ssp trifolii the cross-lines are paler than the ground colour, in ssp flava they are darker than the ground colour. Form obsoleta of ssp flava lacks cross-lines and the dark ring around the central spot.
  • Variation
  • Dissection
  • Male genitalia
  • Female genitalia
  • Larva
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  • ssp trifolii
  • ssp flava
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§1 Dungeness, Kent; 25/07/2017; male; fw 23mm; to light
§2 St Mary's, Isles of Scilly; 22/08/2022; male; to light 
§3 St Mary's, Isles of Scilly; 27/07/2025; male; fw 25.4mm
​L1 Lands End, Cornwall; 07/06/2013
All images © Chris Lewis
Page published 29/07/2017 (§1 & L1) | §2 added 08/09/2022 | §3 added and text amended 22/12/2025