The term epidemiological entomology was first coined by Garrett-Jones over half a century ago1 but has been out of fashion for far too long.2 In this issue, Sougoufara et al.3 illustrate clearly just how insightful such an approach can be when applied to characterizing key properties of a dynamic malaria transmission system before and after the scale-up of vector control with long-lasting insecticidal nets in Dielmo, Senegal. Using simple analytical models first pioneered by Garrett-Jones himself,4 these authors illustrate how not all may be as it appears based on direct interpretation of entomological data alone. Allowing for the fact that malaria transmission requires both humans and mosquitoes to meet at the same time and place, they show that insecticidal bed nets failed to provide direct personal protection against more than one-third of inoculation events at the outset. Even more worryingly, they demonstrate that this gap in personal protection is growing as mosquitoes adapt to bed nets as a normal part of their environment.