Yorkshire Status: Local resident.

It is quite easy for inexperienced moth trappers to confuse August Thorn with September Thorn. The distribution map used to make it easy, with September Thorn in the middle of the county and August Thorn in the south and east. The situation has become a little more complicated in recent years as August Thorn has started to turn up in areas where it really ought not to occur such as parts of VC62, a site north of Ripon and even Harewood House north of Leeds. Despite the names, the flight times are identical so don't use that as a feature. One tip is that August Thorn holds its wings at a much lower angle. Also the cross lines do not converge as prominently as September Thorn, and the outer cross line tends to have a "kink" as it nears the costa, though this feature is not foolproof. One feature which is not widely known is that September Thorn has all-yellow legs whilst the August Thorn has 'knee socks' where the lower part of the legs is whitish. Numbers have been fairly stable in recent years and it appears to be more common than it was back in Sutton and Beaumont's time.

Sutton & Beaumont, 1989: Very local. Only recorded from one or two sites in each vice-county, although there would not appear to be any lack of suitable habitat.

Recorded in 80 (40%) of 200 10k Squares.
First Recorded in 1857.
Last Recorded in 2023.
Additional Stats