Adults visit yellow flowers especially composites (dandilion, etc.) and buttercups. Very similar to Cephus spinipes. Cephus pygmeus has bifid claws where the teeth are virtually parallel, whereas spinipes has claws where the inner tooth is erect and distant from the end tooth. In females the sawsheath is set in a direct line with the oblong plate, whereas in spinipes the sawsheath is set at an angle to the oblong plate. The abdomen is marked with yellow bands on at least tergites 4 to 6.
Larvae feed inside the stems of grass.
Size: 5 - 10mm.
Status: Common, widespread.
Distribution: England, Wales
Flight period: May to July
Plant associations: Larvae on cereal crops and grasses including...
Agropyron spp. (couches) (1)
Avena spp. (oats) (3)
Bromus spp. (bromes) (1)
Hordeum spp. (barleys) (1)
Phleum spp. (timothy grasses) (1)
Secale spp. (ryes) (1)
Triticum spp. (wheats) (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
3. Lorenz, H. and Kraus M. Die Larvalsystematik der Blattwespen (Tenthredinoidea und Megalodontoidea). - Abhandlungen zur Larvalsystematik der Insekten No. 1. Berlin: Akadamie - Verlag; 1957.