Both the enantiomers of 9-methylgermacrene-B (1) were synthesized from the enantiomers of methyl 3-hydroxy-2-methylpropanoate (2). The male-producedsexpheromone of the sandfly Lutzomyia longipalpis (the vector of the protozoan parasite Leishmania chagasi) fromLapinha, Brazil, was identified as (S)-1 by GC comparison.