Before you break out the bug spray, take another look at those “mosquitoes” and make sure they are not harmless flies of some other kind. Yes, mosquitoes are flies, in the family Culicidae, and females bite. These common look-alikes are at worst a nuisance.
Midges in the family Chironomidae bear a strong resemblance to mosquitoes in size, appearance, and sheer abundance. They lack the “beak” that mosquitoes do, though. They are aquatic in the larva stage, and vast swarms will emerge from lakes and ponds periodically. Their overwhelming numbers are staggering, and people often flee the humming, buzzing hordes thinking they are mosquitoes. Midges may also be attracted to lights at night (mosquitoes may come, too, but not nearly in such droves).
These flies, in the family Sciaridae, are often found indoors where the larvae feed in the potting soil of overwatered house plants where they eat roots, fungus, or decaying organic matter. Larvae of some outdoor species migrate over the ground in large, amoeba-like masses. The tiny adult flies live only two or three days. They usually can be find drowning in the soap dish.
Known as “daddy long-legs,’ “gully nippers,” and “mosquito hawks,” crane flies are a diverse bunch, representing several families and hundreds of species. Their size is intimidating, but they don’t bite. Those that have a proboscis use it to sip flower nectar. Larvae of some crane flies are sod pests, but most feed on decaying organic matter and help build soil. Most adult “mosquito hawks” don’t eat at all and let alone kill mosquitoes.
These flies are difficult to distinguish from mosquitoes, but they have a pair of stout spurs at the tip of the tibia (“shin”) segment on each leg. They are most common in the understory of damp woodlands, and in hollow logs or caves. Larvae of most fungus gnats feed in fleshy fungi. Larvae of some prey on other insects that they trap in webs of mucous.