General comments:
Extremely local and declining resident.

Adult Dark and Grey Daggers are identical in appearance, though the larvae are quite dissimilar. In both Herts and Middlesex, records of either species have consistently not been accepted by the County Moth Recorder unless they arose from either larval rearing or adult genitalia dissection. This draconian approach has allowed the true distribution of each species to be revealed. All specimens caught near expanses of Blackthorn are particularly worth a closer look as these might stand a higher chance of being "Darks".

	Determination by Genitalia Examination Required

Recorded in 27 (66%) of 41 10k Squares.
First Recorded in 1887.
Last Recorded in 2024.