Though Robson had few records, he suspected that it would occur 'in all places where there is plenty of Scotch Fir'. [...] The species seems to be [...] widespread in Durham, though in TCD's experience never very common. The moths are sometimes taken well away from conifers, for example at the Chester-le-Street trap where they have appeared at intervals of seven-eight years since the first on 19 March 1965. It comes to the Hamsterley Forest trap at the rate of about 20 per annum, and has been often seen when 'sallowing' at night-time on Waldridge Fell. [...] D. A. Sheppard and M. Eyre listed seven sites in Durham, mostly in the Derwent valley. Caterpillars, when they can be obtained, are not difficult to rear, nor heavily parasitised. Moths can be on the wing from early March to mid-May, according to season.