Easily recognised as the only Cephus species with an all black abdomen, although occasionally British specimens have yellow flecks on the lateral margins of some tergites. The sawsheath is set in a straight line with the oblong plate. Cephus nigrinus appears to be a woodland species in the Britain.
Larvae feed by boring into meadow grass.
Size: 7 - 10mm
Flight period: May to July
Plant associations: Poa pratensis (smooth meadow-grass) (1)
1. Benson, R.B., 1952. Handbooks for the Identification of British Insects. Hymenoptera, Symphyta, Vol 6, Section 2(a-c), Royal Entomological Society, London
2. 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