Wheat Stem Borer - Cephus pygmeus

5-10mm. The commonest of the three Cephus species, often found visiting yellow flowers such as dandelions and buttercups. The abdomen is long and thin - black with narrow yellow bands. The wings are clear with a dark stigma. In females, the hind tibia is mainly dark, possibly with yellow just on one side.

Cephus spinipes is very similar but has bifid claws where the inner tooth is more perpendicular and not in line with the terminal tooth. Females have a yellow hind tibia with black just at the apex.

• More swollen antennal club (pre-apical segments broader than long)
• Hind tibia with darker markings on inner side at apex or over all of tibia
• Sawsheath protrudes inline with body profile when viewed side-on
• Claws bifid at the apex – the teeth being more or less parallel

Microscopic examination is necessary. Please comment how you reached an ID.

Around fields where wheat is grown.

Peak is June and July.

The larvae bore into the stems of wheat and a few other cereals and grasses.

Widespread and thought to be fairly frequent in England and Wales.

Status in Leicestershire and Rutland not known.

https://www.sawflies.org.uk/cephus-pygmeus/