Overall a black insect with reddish-yellow legs which may be infuscated on the apices of the tibiae and tarsi. In the male, the tegulae, underside of the antennae and the hypopygium are brown. In the female, the edge of the pronotum and more or less the underside of the abdomen are brown. Sawsheath not projecting as far back as the long cerci.
Platycampus luridiventris larvae are unmistakable, being flattened against the leaf surface. They feed on alders.
Size: 5 - 6mm
Distribution: England, Scotland, Wales, Ireland
Flight period: May to June
Plant associations: Alnus spp. (alders)
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