[Trematodes of birds (Aves) from the Middle Volga region. 1. Orders Brachylaimidae, Cyclocoelida, Echinostomatida, Notocotylida, and Opisthorchiida].

The data on trematodes of the orders Brachylaimidae, Cyclocoelida, Echinostomatida, Notocotylida, and Opisthorchiida from the Middle Volga region are given. Records of different authors are supplemented with the results of our own research. Reliable records are confirmed for 61 trematode species. The following characteristics for each parasite species are given: the systematic position, the host spectrum, locality, collecting sites, biology, degree of host specificity, and the geographical range. Morphological descriptions and original figures of 3 trematodes species are given.