Females: 5.0-6.5mm, males: 4.5-5.5mm. A largely orange/yellow sawfly with varying black markings. Female mesopleura are shining and without surface sculpture. Females are typically pale with much of the head, the mesopleura, tegulae, edge of the pronotum, legs and the apex and underside of the abdomen all being yellow. The sawsheath when viewed from above is very narrow.

Males have the mesopleura entirely smooth and the hind femora and the tegulae mostly pale.

Euura viduata larvae feed on Grey Willow, Eared Willow, Goat Willow and Creeping Willow.

Spring.

Uncommonly recorded but widespread.

Rare or under-recorded.