Barred Rivulet Geometridae

Perizoma bifaciata (Haworth, 1809)

Description: Wingspan 20-26mm. Adults generally pale grey with a darker central band. The inner and outer margins of the band are much lighter and quite distinctive.

Key Identification Features:

Sets:  male upperside

Flight Period: From late July to early September.

Status: Scarce, recent records only from a few sites in east Down and Rathlin Island, Antrim. Recorded in the early 1990s from Helen's Bay and Killard Point, 1996; Ballydorn near Killinchy 1998 and most recently Rathlin Island, Antrim, and Castle Espie and Ballyquintin Point on the tip of the Strangford peninsula, Down. There are old records from the Cookstown area, Tyrone and Banagher Glen, Londonderry in the 1970s.

Ecology: A scarce, coastal species that is seldom encountered at light. The larvae can be found in September and October inside the seed heads of Red Bartsia Odontites vernus and also eyebrights Euphrasia (the latter being common at most of its recently known localities). Its elusive nature makes it difficult to ascertain its true distribution. However it may well exist in small populations in other localities on the south Down coastline. It overwinters as a pupa.

World Distribution: Central and Southern Europe.

Bradley & Fletcher number: 1804 Agassiz number: 70.134

Additional information:

UK Moths account

Caterpillar: 

 Thompson, R. S. & Nelson, B., 2003 (Oct 2). [In] The Butterflies and Moths of Northern Ireland
http://www.ulstermuseum.org.uk/lepidoptera/species.asp?item=5884

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