Dark Dagger Acronicta tridens
([Denis & Schiffermüller], 1775)
Wingspan 35-45 mm.
This moth cannot be readily distinguished as an adult from Grey Dagger (Acronicta psi) except by examination of the genitalia, although in the caterpillar stage this is not a problem as the species are quite different.
It is widespread in England and Wales, though less common than Grey Dagger, although its true status is perhaps clouded by the identification issue.
The moths fly in June and July, and the larvae feed in the autumn on a range of trees and shrubs such as hawthorn (Crataegus) and blackthorn (Prunus spinosa).