Lepidoptera The Grey Dagger Moth – Acronycta Psi

The Grey Dagger Moth Fig. 139.-The Grey Dagger.

This is the commonest of all the Bombycoida. It may be found at rest on tree trunks and palings during the daytime throughout the summer. Its fore wings are pale grey, with four conspicuous black marks, one of which-that in the anal angle-resembles the Greek letter psi (ψ) placed sideways.

The larva is black or very dark grey, with a pale yellow line down the back, and a black hump on each of the fifth and twelfth segments, that on the fifth being much larger than the other. It feeds in the autumn on lime (Tilia vulgaris), blackthorn (Prunus spinosa), whitethorn (Cratagus oxyacantha), fruit trees, and various other trees, shrubs, and herbs.

The moth called the Dark Dagger (Tridens) is hardly to be distinguished from Psi. It is not really any darker, and its markings are almost exactly similar; but the larva is very different.