Stenopogon inquinatusLoew forages across a wide range of diurnal temperatures. Changes in perch height and body posture allowed the flies to maximize air temperatures experienced when environmental temperatures were low and to encounter a relatively narrow range of air temperatures in the middle of the day. In addition, early in the day they basked by orienting their longitudinal and dorsoventral body axes perpendicular to the sun. Their behavior varied with environmental temperatures in ways that indicate that perching flies thermoregulate by influencing radiative heat gain and the air temperatures and wind speeds that they experience.