Fifteen new Zygomyia Winnertz species are described from material collected from one location in Ecuador during a very short time period: Z. acrotricha sp. nov., Z. comata sp. nov., Z. diversiseta sp. nov., Z. flamma sp. nov., Z. geniculata sp. nov., Z. longistyla sp. nov., Z. napoensis sp. nov., Z. paniculata sp. nov., Z. pectinella sp. nov., Z. spinosa sp. nov., Z. talpaeforma sp. nov., Z. trilobata sp. nov., Z. triseta sp. nov., Z. uniordata sp. nov. and Z. ximoi sp. nov. Zygomyia bicolor Edwards, 1934 is redescribed, including detailed illustration of the male terminalia. The number of Neotropical Zygomyia species is increased to 30. An updated key to the Neotropical Zygomyia is provided. Unexpectedly high level of interspecific genetic variation between Neotropical Zygomyia spp. is reported.