Twenty-two species in the Spissipes Section of Culex (Melanoconion) are recognized and two taxonomic changes are made: Culex alvarezi Sutil Oramas, Pulido Florenzano and Amarista Meneses is synonymized with Culex spissipes (Theobald), and Culex nicaroensis Duret has been determined not to belong to the subgenus Melanoconion and is here treated as a member of the genus Culex without subgeneric assignment. Descriptions of adult female and male, female cibarium, and genitalia of both sexes are provided. Eight groups and three subgroups are characterized. Available data on distribution and bionomics of each species are given. Maps showing the entire known range of the species are given. Keys for species identification based or morphological characters of adults and male genitalia are provided.