The distribution of female mosquitoes about a flight barrier.

A 6.1 m long suction trap, with multiple air inlets located on its upwind, top, ends and downwind sides, was placed on a freely pivoting raft moored in a large borrow pit. Air inlets on the downwind side made larger captures than those on the upwind side. Inlets near the top edge of the trap captured larger numbers than those at the bottom. Larger proportions of Culex nigripalpus and Cx. erraticus accumulated behind the horizontal and vertical edges of the trap than did other species. Mosquitoes near the ends of the trap could choose whether to fly over or around the trap; most Cx. nigripalpus and Cx. erraticus flew over the trap while only Cx. pilosus favored going around the ends. Other species appeared to fly over and around the trap in approximately equal numbers. No evidence was found that flight patterns changed with differing wind velocities.