Insecticidal effectiveness of intervention programmes depending on coverage. The proportion deterred from entering, δ, is kept constant at 0.4, the proportion dead out of those that entered in an untreated control hut, μ0⋆, is kept constant at 0.20, and the proportion of mosquitoes dead in an experimental hut out of those that entered, μ
⋆, is kept constant at 0.8. Also, the proportion repelled (unfed alive mosquitoes) out of those that entered is kept constant at ρ
= 0.3 and ρ
= 0.1 for treated and control huts, respectively.