By reason of their autecology and synecology, Homo sapiens and Aëdes aegypti developed close interspecies associations which served to the detriment of man and the benefit of the mosquito. During the current century the tables were reversed and the underdog became the mosquito. When its role as a vector of yellow fever had been demonstrated by the scientific method, technology—the handmaiden of science—was applied with ever increasing effectiveness to the destruction of this insect species. The control of A. aegypti is an outstanding early example of “species sanitation” and “species eradication,” both practiced at the turn of the century. Entomologists, who previously had concentrated their efforts on other groups of insects, were now motivated by practical considerations to include mosquitoes in their objects of study, for the occasion was instant. During the period from 1762, when A. aegypti acquired a species name, to 1900, when its importance in mass human disease was clearly proved, this insect was regarded as nothing more than a pest by the laity and as an object of curiosity by those interested in natural history.