Semudobia betulae (Winnertz, 1853)

(Figure 57 A)

Material: AK, Oslo: Ellingsrud, Munkebekken, 59.931515°N 10.913550°E ± 20m, 14 March 2019, on Betula pendula, LMF, leg. HE, coll. NHMO; 23 February 2021, on Betula pendula, MF, leg. HE, coll. NHMO; NSY, Gildeskål: Inndyr, Holmvatnet, 67.053984°N 14.072232°E ± 100m, 21 July 2019, on Betula pubescens, L, leg. HE, BOLD: NHMO-ENT-547978, coll. NHMO .

Biology: The orange larvae develop individually in seeds of Betula nana, B. pendula and B. pubescens ( Betulaceae). Infected seeds are swollen, have reduced wings, are partly covered with a felt-like pubescence, and have a round, thin-walled “window” on one side, from which the midge will emerge. Univoltine. The larva hibernates in the gall and pupates there in the spring.

Distribution: Widespread Palearctic, including Norway, Sweden, Denmark and Finland. Introduced to the Nearctic.