Small Rivulet Geometridae

Perizoma alchemillata (Linnaeus, 1758)

Description: Wingspan 22-24mm.

Similar Species: Adults resemble the Rivulet P. affinitata in colour and markings but have a double indention in the inner margin of the band and are smaller.

Key Identification Features:

Sets:  male upperside

Flight Period: From late May to the end of August.

Status: Common and widespread in eastern counties with scattered records from the north (including Rathlin Island) and a few localities in the west namely Crom Estate, Garvary and Tullyreagh Bridge, Fermanagh. Recorded frequently in north Armagh at Peatlands Park and the Argory; also Lackan Bog and Belvoir Park Forest, Down. More commonly encountered than the Rivulet P. affinitata.

Ecology: A species normally associated with woodlands, bogs, and marshy areas. Adults come frequently to light in small numbers. The larvae can be found in August and September on hemp nettles Galeopsis. It overwinters as a pupa.

Bradley & Fletcher number: 1803 Agassiz number: 70.133

Additional information:

UK Moths account


 Thompson, R. S. & Nelson, B., 2003 (Oct 2). [In] The Butterflies and Moths of Northern Ireland