The London Underground mosquito is a form of mosquito in the genus Culex. It is found in the London Underground but has a worldwide distribution. It was first described as a distinct species by the biologist Forsskal in 1775, which he named Culex molestus due to its voracious biting, but later biologists renamed this mosquito Culex pipiens f. molestus because there were no morphological differences between it and Culex pipiens. Notably, this mosquito assaulted Londoners sleeping in the Underground during the Blitz, although similar populations were already known. The most recent research analyzing DNA microsatellites suggests that Culex molestus is likely a distinct species from Culex pipiens.