Size 10mm. The adult sawfly has a black head and abdomen and a bright red top to the thorax. The head and sides are heavily punctured. The mid and hind tibia are pale around the 'knees'.

Similar to Eutomostethus ephippium which is smaller, less punctured and has red sides to the thorax as well as the top.

Around Alder Alnus glutinosa.

May to August

The larvae are up to 2 cm long and covered in a white powdery substance. They camouflage themselves as bird droppings. The white powdery substance is easily rubbed off and in the final instar, when feeding is finished, the white powder is lost and the larva adopts a pale green appearance. There are two generations each year.

Found throughout the UK but most records come from the south.

Common in Leicestershire and Rutland.

https://www.sawflies.org.uk/eriocampa-ovata/