Sweep-net and sticky-trap data were used to examine the influence of time of day (morning, afternoon, evening), trapping location (pasture, bog, fen, regrowth, and mature forest), and meteorological factors (wind, temperature, saturation deficit, and light) on adult female fly catch for three species (species complex) of black flies — Simulium truncatum/venustum complex, Prosimulium mixtum, and Stegopterna mutata (triploid). Wind speed, light, temperature, saturation deficit, and time of day were all shown to have a significant effect on mean catch, although effects varied among species. After accounting for weather and time, trap location was shown to have a significant effect on mean catch. The effect of site on the mean fly catch of S. truncatum/venustum complex varied with season (June to July), which may have resulted from a seasonal shift in sibling-species composition. Mean catches of P. mixtum and St. mutata were lowest in traps located in open habitats.