The Triangle Heterogenea asella
([Denis & Schiffermüller], 1775)
Wingspan 15-20 mm.
This rather small species (around 20mm wingspan), is local and scarce in Britain, only occurring in parts of south-east England.
Inhabiting woodland areas, the recorded larval foodplants are oak (Quercus) and beech (Fagus). However, the species was recently discovered in West Sussex feeding on both horse chestnut (Aesculus hippocastanum) (see photo), and small-leaved lime (Tilia cordata), both of which are previously unrecorded foodplants in Britain.
The strange, grub-like larvae have very short legs and a retracted head.
The adults fly in June and July and are attracted to light.