The developmental rate under low temperatures and cold tolerance were investigated in embryos of the blowfly Lucilia sericata.The larvae of this species are now widely used in maggot debridement therapy.Embryonic development was dependent on temperature,with a lower developmental threshold of 9.0℃.The duration of the egg stage at a rearing temperature of 25℃ was 14 h,and a low temperature of 12.5℃ successfully prolonged this period to 66 h.Embryonic stages differed markedly in their cold tolerance;young embryos were less tolerant to cold than old ones.Late embryonic stages are suitable for cold storage at 5℃ and the storage for 72 h did not decrease the hatching rate by more than 50%.In the mass-rearing process required for maggot debridement therapy,either of these two simple protocols would be beneficial.