Schematic presentation of the life cycle of Anopheles gambiae (s.l.). Immature mosquitoes progress at temperature-dependent rate m. They are liable to die at daily rate 1-s. Upon completion of immature process they form mature mosquitoes which begin a gonotrophic cycle with progress rate PR. They are liable to die at a rate of 1-a per day. New mosquitoes are being imported with rate trickle2. Each mosquito as oviposition lays gRd eggs.