The larva that emerge develop just below the water's surface. They may take only a few days to go through several molts, eventuating in pupae — odd-shaped "tumblers". Both larvae and pupae are active, and both breathe through tubes connected to the surface.

The adults that emerge in a few days feed primarily on plant nectar and other plant juices. But the adult female, in order to develop eggs, generally needs to consume blood. We can be thankful that for a few species this is not required (and selfishly a little thankful that for other species the preferred blood is not human).

Males live only a few days, and at the height of the season, life may be almost as short for females. But in some species, females may live several months, and may hibernate through the winter to emerge in the spring.

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