The Nematocera (thread-horns) are a suborder of elongated flies with thin, segmented antennae and mostly aquatic larvae, consisting of the mosquitoes, crane flies, gnats, black flies, and midges. Nematocera are typically characterized by filamentous, multisegmented antennae which may be plumose in some males. Many species form mating swarms of males, and in some of these, competition for females is extreme. Although many species (as larvae) have a strong association with water, even within a single family there may be a trend toward semiaquatic and terrestrial habitats.