A continuous cell line (M. S. A. p.-1) was obtained from the ovaries of diapausing pupae of the oak silkmoth Antheraea pernyi. Active multiplication of cells was observed two months after preparing a primary culture from partly trypsinized tissues. Subcultures derived at this time were transmitted with 10 day intervals and endure over 30 passages. The cells are susceptible to the nuclear polyhedrosis viruses of Mamestra brassicae, Galleria mellonella, Malacosoma neustria and Bombyx mori.