An egg parasitoid, Trissolcus japonicus(Ashmead) (Hymenoptera: Scelionidae), was reared on eggs of Plautia staliscott (Hemiptera: Pentatomidae), Halyomorpha halys(Stål) (Hemiptera: Pentatomidae), and Glaucias subpunctatus(Walker) (Hemiptera: Pentatomidae), and parasitism rates and developmental properties were compared to clarify their suitability as hosts. The parasitoids successfully emerged from more than 90% of P. stalior G. subpunctatuseggs,whereas a lower rate of T. japonicusemerged from the eggs of H. halys.The developmental period of T. japonicusin the eggs of H. halyswas longer than in the other two species, and the body size of T. japonicusthat emerged from the eggs of H. halyswas also larger than from the other two species. From these results, factors related to parasitism and developmental properties were discussed.