The occurrence ofCoquillettidia perturbans(Walker) in subtropical Florida was monitored for 3 years by larval sampling and emergence trapping. Emergence was nearly continuous between mid-March and early November, but not detected at other times. Peaks of adults in mid-June and early September suggested the occurrence of two overlapping generations. Larvae attached to cattail roots overwintered in the 3rd and 4th instars. Larval densities were higher in late autumn and winter than in summer, were negatively correlated with water temperatures, and were positively correlated with average age (instar)of samples. The number of larvae per cattail and root weight were positively correlated. Approximately 50% of larvae detached during uprooting.