[Conditional suppression of a reflex in Drosophila melanogaster: acquisition and extinction].

In Drosophila it was possible to carry out a negative instrumental conditioning of the tarsal reflex (extension of the proboscis in response to a sucrose stimulation of the forelegs) : the insects could be trained to inhibit this reaction through a repetitive association of its releasing with a consecutive nociceptive stimulation. An experimental extinction procedure allowed the reflex to be resoted.