Oak Slug Sawfly - Caliroa annulipes

The common name comes from the slug like appearance of the larvae and the fact that Oak is often favoured as their host plant, although other trees such as Lime are used.  The larvae are quite transparent when young, becoming greener with age. The larvae of Caliroa annulipes lack yellow at the head end - as seen in some other Caliroa larvae. The adult sawflies are 4-6mm long and are black with pale legs.

This species has a red ID rating and unless identified by a known expert you must provide a satisfactory explanation of how it was identified for the record to be accepted.

Larvae can be found on the leaves of Oak, Birch, Willow, Lime, Beech and Bilberry.

Adults from May to August. The larvae most likely to be found in early autumn.

The larvae feed on leaves, favouring Oak but also using other species such as Lime.

Fairly common in Britain, but under recorded.

Status in Leicestershire and Rutland not known.

https://www.sawflies.org.uk/caliroa-annulipes/