The prevalence and dispersal of Chironomidae in a lake city of Florida was studied. Daily collections of midges from New Jersey light traps placed at the lake front, and 200 m and 400 m away from the lake were made from January 1980 to December 1981. Glyptotendipes paripes, Chironomus crassicaudatus and C. decorus were quantitatively important. Glyptotendipes paripes formed 79.1 and 37.6% and C. crassicaudatus 16.7 and 47.1% of the total adults collected in 1980 and 1981, respectively. On some occasions, each of these two species amounted to 100,000 to 350,000 adults per lake front trap in one night. There was a natural decline of 41% of total chironomids in 1981 compared to 1980. The lake front traps collected 95-100% of G. paripes and 88-100% of C. crassicaudatus, in 1980. There was a gradual decline of the two species in relation to the increasing distance from the lake. Chironomus crassicaudatus seems to be a stronger flyer than G. paripes. It occurred in higher proportions than G. paripes in the farther traps from the lake.