Wingspan c. 15 mm
A number of the British Ancylis species are rather similar in appearance, whereas laetana displays an unusually whitish (for the genus) forewing ground colour.
The species is distributed most commonly in the south-east and south of England, but occurs in scattered locations northwards to Scotland.
Flying in May and June in a single generation, the adults appear from dusk onwards and later come to light.
The foodplants are aspen (Populus tremula) and occasionally black poplar (P. nigra).