Class Insecta: Insects » Order Diptera: True Flies » Family Cecidomyiidae: Gall midges » Dasineura urticae (Perris, 1840)
Gall diameter 8 mm.
A tiny Cecid fly called Dasineura urticae causes these swellings to form on Stinging Nettles (Urtica dioica).
The eggs are laid at the base of the leaf or in a leaf vein. The hatching white larva then forms a pouch, which can range from green to purple, in which it feeds on the plant tissue.
Found wherever the host plant Urtica dioica grows. Common and widespread throughout Britain.