Flies in the Drosophila (Sophophora) obscura species group are among the most common native drosophilids in northern temperate and boreal forests; southward, into cool, montane tropical forests they are rare and localized, but diverse. Of the world's 48 species, 18 occur in the New World, including three new neotropical species described here. Here, all New World species are diagnosed, many with images and the use of some new morphological features such as female terminalia (oviscapt and spermathecal structure). A basic phylogenetic scheme of relationships based on 19 morphological characters corresponds well with molecular trees.

Type series have been rediscovered of D. algonquin, athabasca, azteca, narragansett, and seminole (all described by Sturtevant and Dobzhansky in 1936), from which a lectotype is designated for each of the first four species and the holotype is recognized for seminole. Drosophila narragansett from the eastern United States, which has been found only once in 60 years, is redescribed in detail from historical material; D. seminole is found to be a synonym of narragansett. The three new species are Drosophila chibcha, n. sp. (from Costa Rica to Venezuela and Peru), D. olmeca, n. sp. (from southern Mexico), both of these in the affinis subgroup; and D. zapoteca, n. sp. (from Guatemala), in the pseudoobscura subgroup. Significant new distributional and host records are reported for various species.