Fly

True flies are insects of the order Diptera. Their most obvious distinction from other orders of insects is that a typical fly possesses a pair of flight wings on the mesothorax and a pair of hind wings on the metathorax.

Because no species of fly has teeth, or any other organ or limb that allows them to eat solid foods, flies consume only liquid food or finely granular foods, such as pollen. Their mouthparts and digestive tracts show various modifications for such diets.