Larvae of Megacerus flabelliger Fåhraeus were found in Venezuela feeding in seeds of Merremia macrocalyx (Ruiz and Pavon) O'Donnell, a convolvulaceous weed about which little is known regarding its natural enemies. In the study locality, M. macrocalyx produces fruits with one to four seeds. The bruchid oviposited more frequently on fruits with multiple seeds but only one seed was attacked, although in some fruits with multiple seeds almost all seeds had eggs. Oviposition occurred most frequently on seeds still on the plant. Only M. flabelliger eggs were noted on the seeds of M. macrocalyx. While on a few seeds there was more than one egg attached, most seeds held only a single egg and only one adult emerged from a seed. Wasps belonging to the families Braconidae, Eupelmidae, Eurytomidae and Eulophidae emerged from seeds not destroyed by the bruchid.