Bombus (Psithyrus) campestris
Bombus campestris is one of the most common cuckoo-bumblebees of Europe. It is widespread from the N. Spain, the S.Italy and the Balkan to the South reaching the middle of Fennoscandia to the North. It extends to the Far East of Russia to the East. It inquilines mainly B. pascuorum and other species of the subgenus Thoracobombus.