Mosquito surveillance was conducted in 42 underground parking lots in the densely populated metropolitan area of Wuhan, Hubei Province, central China from Aug to Oct 2012. Autogenous Culex p. molestus mosquitoes, which inhabit underground sites elsewhere in China, were identified and recorded for the first time in Hubei Province. Also Culex quinquefasciatus and intermediates (presumably with Cx. p. pallens) were identified from the samples, but Cx. p. pallens, which is known to hybridize with Cx. quinquefasciatus, was not found during the study. We attempted to determine how to differentiate between the subspecies of the Culex pipiens complex in Wuhan. In the female wings of Cx. p molestus, the subcosta intersected the costa beyond or at the furcation of R_{2 3}; however in Cx. quinquefasciatus and intermediates, the subcosta intersected the costa before the furcation of R_{2 3}. In female abdomens of Cx. p. molestus, lateral patches on tergum II reached the posterior margins; however in Cx. quinquefasciatus and intermediates, the lateral spots on tergum II did not reach the posterior margins. In the male genitalia of Cx. p. molestus, the DV/D ratios were -0.125 to 0.104 with a mean of -0.016 (n = 102), and DV/D ratios ≤ 0 were frequently found (68%). The dorsal arm of the phallosome of Cx. quinquefasciatus and intermediates usually was slightly divergent outwardly, and DV/D ratios were 0.316 to 1.571 with a mean of 0.582 (n = 118). Nineteen percent were intermediates with DV/D ratios between 0.2 and 0.4. Eighty-one percent were Cx. quinquefasciatus in which DV/D ratios between 0.4 and 0.6 were found frequently (53%). Culex p. molestus could be distinguished from Cx. quinquefasciatus and intermediates through characteristics of the female wing, the abdominal terga, the male scutum and the phallosomes.