TARSAL SENSITIVITY OF FEMALE TABANID FLIES TO SUCROSE AND SODIUM CHLORIDE

The foretarsi of females of the tabanid flies, Tabanus lineola Fab., Chrysops vittatus Wied., and Hybomitra lasiophthalma (Macq.), possess contact chemoreceptive sensillae that are sensitive to sucrose and sodium chloride solutions. The tarsi play an important part in the discrimination of acceptable substrates from unacceptable ones.Differences were exhibited between the tarsal acceptance thresholds for sucrose solution; that of T. lineola was 0.05 M −0.025 M, of C. vittatus 0.0125 M −0.0625 M, and of H. lasiophthalma 0.025 M −0.0125 M. The tarsal rejection threshold of NaCl in 0.5 M sucrose solution for T. lineola was 0.80 M, for C. vittatus 0.90 M, and for H. lasiophthalma 0.90 M.