By contrast to the last species [Xylena vetusta], this has declined in the north-east, in with a generalised decrease in numbers over much of the British Isles. [...] In Durham the decline has not been so evident [as in Northumberland]. TCD took it on Waldridge FeIl and in his garden at Chester-le-Street several times during the 1950's and 1960's. in 1966 two from about a dozen larvae on Chrysanthemums were boxed in August with leaves, and duly produced imagines in October of that year. R. Harris found it at light in the hospital grounds at Chester-le-Street in October 1955, and more recently M.Mann captured a specimen at Sacriston on 31 April 1975 after hibernation. It is, however, seen distinctly less often in the county than formerly.