The antennae are long and simple and they have chewing mouthparts. The legs are similar in size and shape. The majority of the Diptera are small and soft-bodied insects. They have only one pair of membranous wings. The hind wings are reduced to small knobbed structures called halteres that are used as organs of balance during flight.
Many flies also have a calypter or membranous lobe at the base the wings.
They have large compound eyes and the mouthparts are adapted for sucking, piercing or sponging. The larvae, called maggots, are legless and wormlike . Mayflies Mayflies are small to medium sized, elongate, and very soft-bodied. The abdomen is long and slender with two to three long threadlike tails. Adults have two pairs of membranous wings with numerous veins.