The percentage mortality of Anopheles gambiae s.s . S-form from Soumousso following one-hour exposure to deltamethrin (0.05%) at three to five and 17-19 days old. Two separate assays (Assay 1 and Assay 2) were performed on pooled S-form An. gambiae s.s. isofemale families. Different notations represent significant differences in mortality between age-groups within each test (p < 0.0001).