Polyembryony in Holcothorax testaceipes (Hymenoptera: Encyrtidae)

Holcothorax testaceipes (Ratzeburg) is polyembryonic with a mean of 11 parasitoids per brood when reared on Phyllonorycter ringoniella Matsumura and 12 when reared on P. blancardella (F.). Most broods contained either only males or only females; mixed broods were rare. The sex ratio was approximately 1:1. During the embryonic and sap-feeding stages of the host, parasitoid eggs underwent maturation, dividing the embryonic cells into a number of primary masses. When the host reached the tissue-feeding stage, the polygerm was well developed and had begun to dissociate into individual embryos. Individual embryos were well differentiated in the early prepupal host. After consuming the entire contents of the host, the free parasitoid larvae reached maturity and formed discrete pupal cells in the distended cuticle of the host.