Pestiferous slugs in organic and conventional farming systems damage crops, reduce yield and quality, and reduce profits; however, no biological control agent that is both efficacious and inexpensive has yet been developed. One potential biological control agent is the slug-feeding Tetanocera elata (Fab.), for which scant scientific data are currently available regarding optimum growing conditions. This study examined the effect of constant temperatures (14, 17, 20, 23 and 26°C) and ambient outdoor and laboratory temperatures on the duration of the egg stage of T. elata. In general, mean and median duration of incubation decreased as temperatures increased, with the highest (52%) and lowest (20%) hatch rates occurring at 14 and 26°C, respectively. Longevity and oviposition rates for T. elata are discussed in the context of mass biocontrol production systems, and possible reasons for low hatch rates for eggs stored at 2–3°C are discussed in the context of the phenology of the species.