Psychoides verhuella

Larvae feed from August to June, initially in a whitish mine in the frond, and in the spring they leave the mine and burrow into a sorus, feeding on the sporangia. They later form a loose, portable case from empty sporangia and when fully grown in May the case resembles a misplaced sorus, especially on hart's-tongue fern (Asplenium scolopendrium). The larva is yellowish white with a brownish dorsa line and has a black head and black prothoracic plate.^[2]

The following ferns have been recorded as food plants,^[3][4]

• rustyback (Asplenium ceterach)
• wall-rue (Asplenium ruta-muraria)
• hart's-tongue fern (Asplenium scolopendrium)
• maidenhair spleenwort (Asplenium trichomanes)
• bracken (Pteridium aquilinum)

Larva of another moth, Psychoides filicivora also feed on ferns. It has a pale-brown head and a pale-brown posterial margin, which has a split in the middle, compared with the black head and prothoracic plate of Psychoides verhuella.^[5][6][7]

In a larval case, which is often against the midrib of the food plant.^[4] Can be found in May and June.^[8]

Single brooded, the moth flies in June and July, in early morning and late afternoon sunshine. Occasionally comes to light.^[9] The grey to dark grey monochrome forewings have a violet reflection and lack the white tornal spot of Psychoides filicivora. The antennae are wire-shaped and just over half as long as the front wings.

Found in Europe, this species has been recorded from the following countries and regions; Austria, Belgium, Channel Islands, Czech Republic, Germany, Great Britain (local distribution), Hungary, Ireland, Poland and Romania.^[10]

Psychoides was raised by Charles Braund in 1853 and comes from psukhē – of the soul, i.e. a moth of the family Psychidae and eidos – form, that is from the similarity of this species to moths of the Psychidae. The specific name verhuella is in honour of the mid-19th century Dutch entomologist, Q M R Verhuell.^[11]