Counts were made of Microdiptera hatching in emergence traps from samples of organic substrates from cacao plantations in Bahia, Brazil. Rotten cacao pods provided the best substrate with regard to species diversity and total numbers of insects collected, and also for the subgenus Thyridomyia. Leaf-litter was found to be an important breeding place for the subgenus Forcipomyia, especially F. {F.} genualis (Lw.), and for Atrichopogon species. Epiphytic bromeliads may be an important breeding place for the pollinating subgenus Proforcipomyia.