Wyeomyia exallos
, a new mosquito species from Atlantic Forest of southeastern Brazil, is described based on morphological characters of the adult female, male, male genitalia, pupa and fourth-instar larva. The morphological characters of
Wy. exallos sp. nov. are compared with those of different subgenera of
Wyeomyia as well as of species without subgeneric position. It is proposed that the new species should be placed in genus
Wyeomyia Theobald without subgeneric assignment.