The responses of four Drosophila species (D. melanogaster, D. simulans, D. immigrans, D. lativittata) to chemicals were tested in a wind tunnel. Methanol, isopropanol and butanol were unattractive, but there was interspecific variation for four of the five chemicals (ethanol, n-propanol, methyl acetate, acetic acid, acetaldehyde) which were attractants. The responses of these species to four fruit odours (apple, plum, peach, lemon) indicated that D. immigrans preferred lemon odours more than did the other species. The relative attraction of D. immigrans to the other fruit odours depended on the combination in which they were presented. These results are compared with earlier findings from Y-tube olfactometers, and their relevance to differential resource attraction in the wild is discussed.