Culex tarsalis larvae derived from field-collected egg rafts were reared outdoors in a deep pond with constant water temperature or a shallow pond with fluctuating temperature. No significant differences were found between ponds in the proportion of larvae surviving to adults, female autogeny rates or wing lengths of adults. The average time from 1st instar to adult emergence ranged from 8 days at 31 degrees C to 16 days at 17 degrees C. Males developed faster than females, and both sexes always emerged faster from the shallow pond than from the deep one. However, the temperature-adjusted mean emergence times were equal, and normalized cumulative development curves, fitted to a Weibull function, were identical for the 2 ponds.