Development rates for immature stages of the pales weevil,Hylobius pales(Herbst) (Coleoptera: Curculionidae), were estimated over constant temperatures ranging from 9 to 34°C. Development occurred between 9 and 30°C for eggs and 9 and 32°C for larvae; however, the range of successful development for both prepupae and pupae (21–28°C) was much more narrow. Parameters determined for the biophysical model of Sharpe&DeMichele (1977) could be used to predict development of eggs and larvae, but prepupal and pupal development data were insufficient to permit use of this model. Standard cumulative frequency distributions were determined for each life stage and Weibull functions fitted to these data.