Altitude distribution of Tabanidae as determined by Malaise trap collections.

In an investigation of the altitude distribution of host-seeking tabanid females, 2 Malaise traps with openings 0.6 m high were placed on gauze platforms and used to sample tabanid populations at various heights above ground level. A total of 15 species was collected, of which 7, Tabanus abdominalis F., T. calens L., T. fuscicostatus Hine, T. lineola F., T. proximus Wlk., T. subsimilis Bellardi and T. sulcifrons Macq., were present in sufficient numbers for statistical analysis. Seventy per cent or more of the tabanids were collected when the opening was less than 1.8 m above ground. In most instances, a higher proportion was collected at heights between 0.9 and 1.5 m (26.1-65.3%) than at heights between 0 and 0.6 m (14.3-45.8%).