Euura myrtilloides is a species of sawfly belonging to the family Tenthredinidae (common sawflies) and the larvae forms galls on swamp willow (Salix myrtilloides). It was first described by Jens-Peter Kopelke in 1996. E. myrtilloides is one of a number of closely related species which is known as the Euura atra subgroup.
The gall is often low down on the plant and is a conspicuous, elongated swelling on young branches. The larvae over-winter in the gall.[1]
Other similar looking galls in the Euura atra subgroup are,[2]
Recorded from Finland and Norway.[2]