Odonata

Odonata is an of carnivorous s encompassing the  (Anisoptera) and the  (Zygoptera). The Odonata form a, which has existed since the.

Dragonflies are generally larger, and perch with their wings held out to the sides; damselflies have slender bodies, and hold their wings over the body at rest.

These insects characteristically have large rounded heads covered mostly by well-developed, s, legs that facilitate catching prey (other insects) in flight, two pairs of long, transparent wings that move independently, and elongated abdomens. They have three and short. The are on the underside of the head and include simple chewing  in the adult.

Flight in the Odonata is, with flight muscles attaching directly to the wings; rather than indirect, with flight muscles attaching to the thorax, as is found in the. This allows active control of the amplitude, frequency, angle of attack, camber and twist of each of the four wings entirely independently.

In most families there is a structure on the leading edge near the tip of the wing called the. This is a thickened, –filled and often colorful area bounded by veins. The functions of the pterostigma are not fully known, but it most probably has an aerodynamic effect and may also have a visual function. More mass at the end of the wing may also reduce the energy needed to move the wings up and down. The right combination of wing stiffness and wing mass could reduce the energy consumption of flying. A pterostigma is also found among other insects, such as bees.

The nymphs have stockier, shorter, bodies than the adults. In addition to lacking wings, their eyes are smaller, their antennae longer, and their heads are less mobile than in the adult. Their mouthparts are modified, with the labium being adapted into a unique prehensile organ for grasping prey. Damselfly nymphs breathe through external s on the abdomen, while dragonfly nymphs respire through an organ in their.