A new species of Iraella Nieves-Aldrey, Iraella hispanica n. sp. (Hymenoptera: Cynipidae), is described from northeastern Spain. The new species induces plurilocular galls on terminal flower buds of the common poppies Papaver rhoeas L. and Papaver dubium L. (Papaveraceae). The terminal-instar larva also is described. I. hispanica represents the second known species of the genus Iraella and is related to Iraella luteipes (Thomson), a species inducing cryptic galls in stems of Papaver somniferum L. Characters separating adults, larvae, and galls of both species are given as well as life cycle data. Comments on an associated parasitic species of Figitidae, Parnips sp. cf nigripes (Barbotin), are provided. The phylogenetic relationship of the new species with a clade of cynipids associated to Papaver plant species is discussed.