The nettle pouch gall develops in leaf veins, leaf petioles, flower stalks and sometimes the stem of Urtica dioica (and less commonly Urtica urens).

[3] The galls are irregularly shaped, smooth, often shiny, and coloured from purplish to pale green, exhibiting thickened walls, with a narrow slit-shaped opening, normally on the underside.

[1][3] The galls are mainly found around the growing apex and exhibit a wide range of forms, dependent on the organ in which they are situated.

[3] White larvae live gregariously in each gall, feeding upon the plant cell contents.

When larvae reach maturity, they leave the gall to pupate in the soil.