Male: 9 to 12 mm, Female: 10 to 14mm.  Females are a broadly dull dark insect with yellow on the head between the antennae and yellow also are the two basal antennal segments, tegulae, legs and posterolateral flecks on tergites 3 to 7. Darkness of the abdomen is variable from black to yellowish-brown. Males are lighter and have the face and forward parts of the frons yellow with the genae more or less black. The abdomen is often an orangey-brown colour. The larvae are orange coloured with a black head.

Adult Larva

Adult: Unless identified by a recognised expert, a photo is required and the specimen should be examined with a microscope. In the comments box, state the key or ID method used and describe the size and identifying characters.

Larva: Please include a photo with your larval records.

Associated with rosaceous plants including pear, hawthorn and plum.

Adult flight period is May to June.

Larvae feed in communal webs of up to 60 individuals.

Widespread in England and Wales although rather infrequently recorded. 

Rarely recorded in Leicestershire and Rutland.

https://www.sawflies.org.uk/neurotoma-saltuum/