The infection of adult mosquitoes by the entomopathogenic fungus Erynia conica is presented for the first time. Adult Aedes aegypti were exposed to conidial showers from field-collected chaoborid, tipulid and chironomid cadavers for 24 h under conditions of 100% RH and 15 degrees C. Up to 24% of the adults were killed by the mycosis. Cadavers of Ae. aegypti produced conidia that were infective to other adult Ae. aegypti; however, rates of infection were never more than 12%. Nevertheless, Ae. aegypti served as the laboratory host for E. conica via mosquito-to-mosquito serial passages for up to 6 months. Adult Culex restuans were also susceptible to infection by E. conica.