Effect of background contrast on attraction of host-seekingTabanus nigrovittatusMacquart was examined using small test panels against large background panels. Attraction ofT. nigrovittatusto gray test panels was significantly greater when contrast against gray background panels was highest. Maximum numbers were attracted to high-intensity blue test panels against low-intensity gray backgrounds and low-intensity saturated blue panels against all-gray backgrounds regardless of intensity. The latter indicates the attractive effect of hue independent of intensity. Flies collected on test and background panels were clumped on the test panel (32.6%), along the boundary of the test panel and the background panel (59.9%), and from 15.2 to 38.0 cm above ground level (85%). Direct observation revealed that 60% of the flies approaching the panel landed and all did so below the height of initial approach. Only 20% landed immediately; the remainder flew past the panel first, then returned. The majority of flies (85.5%) approached panels at 30.4–53.2 cm above ground level.