The female is very striking with its black and white body and orange wings with yellow stigma, costa and subcosta. The wings in the male are pale brownish and the venation is dark (although the stigma is still yellow in the centre). The white on the male is much reduced but both sexes have white flecks on the lateral face of some of the apical tergites. This species is associated with marshy areas.
Macrophya duodecimpunctata larvae feed on various sedges and grasses in wet habitats.
Size: 10 - 12.5mm
Distribution: England, Scotland, Wales, Ireland
Flight period: May to July
Plant associations: Cyperaceae and Gramineae (sedges and grasses)
Benson, R.B., 1952. Handbooks for the Identification of British Insects. Hymenoptera, Symphyta, Vol 6, Section 2(a-c), Royal Entomological Society, London
Liston A, Knight G, Sheppard D, Broad G, Livermore L (2014) Checklist of British and Irish Hymenoptera - Sawflies, ‘Symphyta’. Biodiversity Data Journal 2: e1168. https://doi.org/10.3897/BDJ.2.e1168