Very similar to Cephus pygmeus. Cephus spinipes has bifid claws where the inner tooth is erect and a little distant from the end tooth, whereas in pygmeus the inner tooth is more parallel to the end tooth. The sawsheath in females is angled relative to the oblong plate. Adults visit yellow flowers such as composites (dandilion, etc.) and buttercups.
Larvae feed inside grass stems.
Size: 7 - 9mm.
Status: Common and widespread
Distribution: England, Wales
Flight period: May to July
Plant associations: Grasses including...
Phleum pratense (timothy-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