Grass Emerald Geometridae

Pseudoterpna pruinata (Walker, 1863)

Description: Wingspan 35-40mm. Freshly emerged adults are bluish-green with darker medial cross lines. The colour pigment is unstable and fades quickly, so the majority of specimens taken at light show little or no trace of green even though they appear to be in good condition. There are two black and one white wavy line across the forewings. The hindwing has a smoothly rounded outline.

Key Identification Features:

Sets:  male upperside

Flight Period: Late June to the beginning of September.

Status: Widespread and commonly encountered in the east but apparently much scarcer in the north and west. The only recent record north of Lough Neagh is from Curran Bog, Londonderry. There is also an old record for Rathlin Island, Antrim.

Ecology: An attractive species that occurs in a wide variety of habitats. Adults come to light in small numbers and can on occasions be disturbed from vegetation during the day. The larvae usually feed at night and can be found from September to May of the following year on Gorse Ulex europaeus and Broom Cytisus scoparius rather than grass as its name suggests. It overwinters as a pupa.

Bradley & Fletcher number: 1665 Agassiz number: 70.297

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=5738

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