Male stable flies,Stomoxys calcitrans(L.), rested on prominent bright sunlit objects near their hosts. On mild days males were present on such objects (waiting stations) throughout the day with peak populations occurring early in the morning. On cool days, male activity was confined to midday. When a waiting station was coated with adhesive, 60% of captured flies were males. Of the females caught, 35–54% were unmated. Ca. 26% of the flies were engorged and ca. 37% had not had their first meal. Stable flies fed on the host throughout the day in mild temperatures, but ceased to feed when the temperature failed to exceed ca. 10°C. Males resting on waiting stations darted out after other flying insects and engaged them in aerial interactions. Observations of marked males indicated that some males maintained their positions several hours while other males remained only a few minutes and left their positions after aerial interactions with larger males. Males also encountered receptive females at the waiting stations. Males mounted females in the air or on the ground but copulation occurred on a perch. During the winter months, stable flies basked in the sun at the waiting stations and were able. to maintain internal temperatures up to 14.8°C higher than ambient temperatures. When internal temperatures reached 31–34°C flies were found at shaded resting sites.