Abstract: Chrysocharis pentheus, an important natural enemy of pea leafminer, Phytomyza horticola, kills its host by both parasitizing and feeding. In the laboratory observations, the female adults of the parasite showed an obvious preference for matured leafminer larvae to newly hatched ones for oviposition and feeding. It was found that 59.4% of hosts killed by the adult parasite in its life span was due to feeding, while 40.5% by parasitization. It indicated that supplementary nutrition was crucial to the parasite\'s survival and reproduction.