AbstractThe venom thatChelonussp. nearcurvimaculatusinjects into each parasitizedTrichoplusia niegg is entirely injected within the first 8 s of the 19‐s oviposition period, before deposition of the parasitoid egg that is injected during the final 1‐2 s of the oviposition. The parasitization factor, causing precocious metamorphosis of the host, is injected after the venom, but before the parasite egg. The venom by itself does not cause developmental redirection of the host.Chelonusvenom proteins are very stable in the host egg during the first 2 days of egg development. Then, on the last day before hatching, they are rapidly degraded by the proteolytic enzymes appearing in 3‐day‐oldT. nieggs. Among those that degrade the venom proteins are serine‐type proteinases, and at least one seems to be a trypsin‐