Amazing feathered antennae
(male). The mis-named Willow Beauty is not one of the most beautiful of
moths, nor does its caterpillar favour willows.
Difficult to tell
Willow Beauty from Mottled Beauty sometimes (see key below)
On forewing of Willow Beauty, second dark line comes close to third dark
line, as illustrated above; on Mottled Beauty (which is very
variable-patterned moth), second dark line ends short or joins middle of
first dark line.