This rare and very local species was, in the early days, known only to J. Gardner, who took it in Hartlepool and Hesleden Dene, where the larvae probably fed on common centaury (although Blackstonia can also be utilised). Nothing was heard of it thereafter until TCD found it on Cronkley Fell and Widdybank Fell in Upper Teesdale (1967 et seq.), here evidently subsisting on Gentiana verna. (Early specimens from these sites confirmed by the late L. Wakely). On 27th July 1990, TCD with Dr. Lewis Davies carried out a survey of insects on Seal Sands (Teesmouth) in connection with a proposal to site a toxic waste incinerator there. The site was covered with common centaury (Centaurea erythraea) and yellow-wort (Blackstonia perfoliata) and S. zophodactylus was swarming everywhere. [...].