Grey Dagger (Acronicta psi) - top view

Image: © Rob Farrow Taken: 21 Jul 2013

This attractive little moth takes its common name, Grey Dagger, from the black markings on its forewings resembling daggers - the "grey" referring to the overall colour of the moth, rather than the "daggers". Its Latin specific name of "psi" also refers to these markings, with their similarity to the Greek letter of that name. Although I have declared this to be a Grey Dagger, there is an outside possibility that it is the less common "Dark Dagger" (Acronicta tridens) but apparently the two species can only be told apart "by a minute examination of the genitalia" - and I would think that they are pretty minute too. Apart from the fact that I wouldn't actually be sure precisely where to look, neither would I be sure what differences I'd be looking for, moths' genitalia not being my specialist subject, I'm afraid. Interestingly the larvae (caterpillars) of the two species are quite different, the Grey Dagger having a prominent "horn" behind its head. Another curious and slightly perverse thing about these two species is that the Dark Dagger is generally somewhat lighter in colour than the Grey Dagger. For a head-on view of this little moth, see Image]

Images are licensed for reuse under creativecommons.org/licenses/by-sa/2.0