The gall can be a smooth, globular or a spindle-shaped swelling on a shoot.

Correct identification of the host species is important, as the gall of R. degeerii is similar to R. salicis.

In Britain the gall on purple willow (Salix purpurea) is recorded as R. degeerii.

[1][2] The insect or gall has been found in Denmark, France and Great Britain.

This article related to members of the fly infraorder Bibionomorpha is a stub.