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A hoverfly, a fly with bee-like markingsA hoverfly, a fly with bee-like markings Flies are insects with only one pair of stiff, transparent wings. The group includes crane flies, gnats and mosquitoes. They are able to fly at high speed and with great agility. Coarse, bristly hairs on their legs and body detect air movement, while their short antennae sense smells and vibrations. Flies' compound eyes give nearly all-round vision. Instead of biting jaws, flies have mouthparts that they use to suck up liquid food. Although some species spread diseases, many flies help to keep our environment clean, by feeding on dung or rotting material such as dead plants and animals.

Chrysops deer fly feedingChrysops deer fly feedingClick to play video


To eat foods that are not already liquids, a fly vomits over them. This liquefies the food so that the fly can suck it up with its spongy mouth. Many flies help to pollinate flowers by feeding on nectar and pollen, while others are scavengers. Some females feed on blood in order to gain proteins needed for laying eggs. In order to get to their warm, liquid meal of blood, they use needle-like piercing mouthparts called "stylets".

A bluebottle, a species of  blow fly, feedingA bluebottle, a species of blow fly, feeding
Fly eggs and maggots on a piece of meatFly eggs and maggots on a piece of meat


There are more than 150,000 known species of fly in the world—and there may be 1 million more species yet to be discovered.

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