Proscopiidae is an orthopteran family endemic to South America. Some species, such as Stiphra robusta, are considered sporadic pests in drought areas in the northeastern region of Brazil. This study establishes, for an undescribed Stiphra species, parameters for stadia and mortality that accompany its postembryonic development, as well as the sex ratio of females (no. female: total emerged adults) under laboratory conditions (67.4% mean relative humidity and 26.7° C). The adult stages were attained by three different developmental regimes involving different numbers of instars: four (4.8% of the population, males only), five (64.5%, sex ratio 0.24) and six instars (30.7%, sex ratio 0.94). The species is univoltine with the following mean duration for postembryonic development: males 71.8 d to complete four instars, 83.8 d for five instars, 110.7 d for six instars; females 85.6 d for five instars and 103.1 d for six instars. Overall mortality from neonates to adults was 13.1%, highest in the first instar.