Very similar to Cephus spinipes. Pygmeus has bifid claws where the teeth are virtually parallel, whereas spinipes has bifid 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.
Status: Common, widespread.
Distribution: England, Wales
Flight period: May to July
Plant associations: Cereal crops and grasses including Agropyron (couch), Avena (oat), Bromus (brome), Hordeum (barley), Phleum (timothy grass) , Secale (rye) and Triticum (wheat)
Adults visit yellow flowers especially composites (dandilion, etc.) and buttercups.
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