Este trabalho foi apoiado pelo Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), sob o prêmio 407475 / 2012-5; Fundação de Amparo à Ciência e Tecnologia do Estado de Pernambuco, sob premiaçãoAPQ-2141-4.00 / 12 PPSUS-FACEPE; e o Instituto Nacional de Alergia e Infecciosidade Doenças dos Institutos Nacionais de Saúde, sob o prêmio R01AI095514 e R21AI128931.Culex mosquitoes are primarily found in temperate and tropical regions worldwide where they play a crucial role as main vectors of filarial worms and arboviruses. In Recife, a northeast city in Brazil, high densities of Culex quinquefasciatus are often found in association with human populated areas. In marked contrast to another part of the city, field tests conducted in the neighborhood of Sítio dos Pintos showed that trapping of mosquitoes in skatole-baited ovitraps did not differ significantly from captures in control (water) traps. Thus, classical and molecular taxonomic approaches were used to analyze the Culex species circulating in Sítio dos Pintos. Results obtained from both approaches agreed on the co-circulation of Culex quinquefasciatus and Culex nigripalpus in three different areas of this neighborhood. What was initially considered as an unexpected failure of this lure turned out to be a more unsettling problem, i.e., the first report in Recife of Culex nigripalpus, a vector of Venezuelan equine encephalitis virus and West Nile virus. Unplanned urbanization processes close to remnants of the Atlantic forest, such as observed in Sítio dos Pintos, may have contributed to the introduction of Cx. nigripalpus in urban areas. This article is protected by copyright. All rights reserved.