Diptera: Tephritidae - fruit fly Gall in achene of Centaurea nigra, Knapweed Hosts: Asteraceae: Centaurea spp, Cyanus segetum, Serratula tinctoria A single larva in a swollen achene with a flimsy wall

Urophora quadrifasciata
Corfe Mullen, Dorset. July 2018