Immatures mouthparts are formed for chewing. Diptera are usually winged, but have only one pair of wings with few veins. Hind wings are represented by a pair of slender, knobbed structures. Mouthparts are formed for sucking or piercing and sucking. Hymenoptera are winged or wingless insects.
Winged members have two pair of wings with few veins.
Mouthparts are formed for chewing or both chewing and sucking. The body is usually constricted greatly between the abdomen and thorax.