Two new Aprostocetus species (Hymenoptera: Eulophidae: Tetrastichinae), fortuitous parasitoids of invasive eulophid gall inducers (Tetrastichinae) on Eucalyptus and Erythrina.

Two closely related new species of Aprostocetus Westwood (Hymenoptera: Eulophidae: Tetrastichinae) are described as fortuitous parasitoids of invasive gall inducers in two other genera of Tetrastichinae, Leptocybe Fisher & LaSalle and Quadrastichus Girault. Aprostocetus causalis La Salle & Wu is a parasitoid of Leptocybe invasa Fisher & La Salle on Eucalyptus spp. (Myrtaceae) in China and Thailand, and A.