A. N. Nilsson 1994: 2 New East Palearctic Agabus Species of the Adpressus Group and Confinis Group (Coleoptera, Dytiscidae). - Entomologica Fennica 5: 169-175.
The Agabus adpressus-group is defined and Agabus udege sp.n. is described from the Sikhote-Alin mountain range in easternmost Russia. It is the sister-species of A. adpressus Aube, 1837. Some East Palearctic specimens previously assigned to Agabus discolor (Harris, 1828), A. clypealis (Thomson, 1867), and A. levanderi Hellen, 1929, in the literature are described as Agabus angusi sp.n. The new species is known from the Lake Baikal region and eastwards to NE Mongolia and northernmost China.