On occasion dragonfly specimens are found. They are a lot more difficult to come by, and so they are more prized by collectors. Fossilized insects are extremely rare, as the insect contains no hard shell or bones to fossilize. This means that the insect must fall into the water and quickly be covered with sediment in order for the insect to be fossilized. Thus, there are very few dragonfly specimens as a very bizarre set of coincidences is needed in order for an insect to be fossilized.
The dragonfly specimens are of cymatophlebis, a Jurassic dragonfly 150 million years old. Prehistoric dragonflies have been documented up to 29.5 inches in length.