* Arthrocnodax fraxinellus (Meade, 1888)

(Figure 26)

Material: VE, Tønsberg: Sem, 59.28387°N 10.33223°E ± 10m, 24 February 2020, L, leg. AF, coll. Private; AK, Asker: Brønnøya, Pilodden plot 41/458, 59.854564°N 10.526731°E ± 3m, 2 April 2019, 1F, leg. HE, coll. NHMO ; Oslo: Tøyen, Botanical Garden, 59.918494°N 10.769993°E ± 5m, 27 April 2017, M, leg. HE & AL, coll. NHMO ; 16 October 2017, L, leg. HE, coll. NHMO .

Biology: The larvae are predators on the gall mite Aceria fraxinivora (Nalepa, 1909) (Acari: Eriophyidae), which induces galls on the female flower stalks of Fraxinus excelsior ( Oleaceae). They develop in the galls of the host, hibernate there, and pupate there in the spring in a white cocoon.

Distribution: Only known from a few European countries including Norway and Denmark.