Summary
Host specificity, attachment sites, infection rates and seasonal variation of Dolops discoidalis and D. bidentata were studied during a one-year period, from March, 1979, to March, 1980, in the vicinity of Janauacá a "varzea" lake in Central Amazonia. Seasonal variation was found to be closely related to water levels with maximun peaks of infestation for both species occurring during high water (June & July), and minimun peaks during low water (October & November). Both species showed low host specificity; D. discoidalis was found to parasitized eight species of fish and D. bidentata six. The first of the specie showed a marked preferece for amooth-skinned fishes while the second was more often collected on scaly fishes. Both species parasitized the external surfaces of their hosts.