A Review of the Species of Drosophila (Diptera: Drosophilidae) and Genera of Drosophilidae of Northeastern North America
By Miller, Meredith E., Stephen A. Marshall, and David A. Grimaldi
"Keys are provided here to the 12 genera of Drosophilidae in northeastern North America, illustrated with photomicrographs of external features. Keys are further provided to the 35 species of
Drosophila in the region, illustrated with photomicrographs of external features and of the male and female genitalia. Each species is diagnosed, with its biology and distribution summarized, based on the literature and examination of over 10,000 specimens (for which all records are provided)."
http://cjai.biologicalsurvey.ca/mmg_31/mmg_31.html