Apanteles porthetriaeMues. andApanteles liparidis(Bouche) are important regulating agents of the gypsy moth,Lymantria dispar(L.), throughout their native range. The failure of these parasites to become established in the U.S. has been attributed to their inability to find suitable alternate hosts. This study examined the status of native Lepidoptera as potential alternate hosts.A. porthetriaesuccessfully developed in 3 native species: the white-marked tussock moth,Orgyia leucostigma(J. E. Smith), the fall webworm,Hyphantria cunea(Drury), and the yellow woolly bear,Diacrisia virginica(F.).A. liparidisdid not develop in any native species.The possibility of the future establishment ofA. porthetriaeis discussed, emphasizing the importance ofO. leucostigmaas an alternate host.