Lesser Treble-bar - Matlock

Brian Statham left me a message earlier this evening to say he thought he had seen one of the Treble-bar's on rough ground opposite Sainsbury's, he was heading up to search. I didn't get home until later by which time he was ringing to say he had counted 15 of what he was fairly sure were Lesser Treble-bar. 
It was getting late when I arrived but I saw at least 5. The two species are difficult to tell apart, the tip of the abdomen is blunt in Lesser Treble-bar and pointed in Treble-bar, the angle of the basal cross-band is slightly acute but this is variable. 
I have previously taken the moth at home as has Simon Roddis also in Darley Dale 

Lesser Treble-bar

Lesser Treble-bar - underside of male abdomen