Circular, lower-surface blotch [mine], about 5 mm in diam, often quite a number together on a leaf. Upper surface wart-like, strongly reddish discoloured, opaque. At the lower surface the mine is closed only by the epidermis. The larva is easily visible, as is its food: drops of liquid resulting from external digestion. Pupation sometimes in the mine, sometimes in the soil. At least two annual generations. Pupa in a white cocoon.. .

The biology of Cystiphora species forms a transition between the mining and galling ways of life.

- Willem N. Ellis: (2021) Plant Parasites of Europe^©

Reference: https://bladmineerders.nl/parasites/animalia/arthropoda/insecta/diptera/nematocera/cecidomyiidae/cecidomyiinae/lasiopteridi/oligotrophini/cystiphora/cystiphora-sonchi/