Forest Preserve District of Cook County, Illinois
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Dragonflies and Damselflies
Nature Bulletin No. 299-A   March 23, 1968
Forest Preserve District of Cook County
Richard B. Ogilvie, President
Roland F. Eisenbeis, Supt. of Conservation

Few creatures are more fascinating to watch than those graceful airplane-like insects which patrol the ponds and streams -- the Dragonflies. In the world of insects they excel in speed, aerial acrobatics and ability to hover seemingly motionless in mid-air. Zooming and darting like fighter planes, the four long narrow wings of the dragonfly move so fast that they blur and buzz like miniature propellers. Their smaller relatives, the Damselflies, have a lazier flapping flight.

About 2700 species of these sun-loving insects are known, mostly in warmer climates where their young grow up in freshwater lakes, ponds and streams. The bodies of most kinds are vividly colored -- red, blue, green or yellow, with spots or stripes on their beautifully veined cellophane-like wings -- the males usually having more brilliant metallic hues than the females. The adults eat enormous amounts of mosquitoes, gnats and other insects which they scoop out of the air in a "basket" formed by their legs and "chest", like a boy catching a football. They chew and swallow their prey, either while on the wing or as they sit alert for another victim, turning their heads from side to side. With a pair of great jeweled eyes covering over half of the head, and a long stream-lined abdomen, they look like some strange flying dragon belonging to the dim past. This is not so far-fetched. They are among the oldest known insects, and fossil dragonflies with a wingspread of two feet have been found in rocks of the Coal Age.

The females often flying "tandem", with the male in front to help break the surface, place their eggs underwater. Other kinds lay them in long strings on aquatic plants. These hatch into tiny six-legged young called nymphs which, after feeding underwater for several months or more, and ten to fifteen molts of their skins, reach full growth. Then the nymph crawls from the water onto some rock, twig or grass blade, the skin splits down the back, and a pale much-rumpled adult climbs out. For protection this usually happens at night. In an hour or so the wings unfold and the adult is ready for its brief life of a few months.

Damselflies can be distinguished from dragonflies because they are more slender and when at rest, instead of holding their wings straight out from their sides, like an airplane, they fold them together over the abdomen, like a butterfly. Their young, too, are distinctively different. Dragonfly nymphs are stocky awkward creatures that lie in wait for small swimming animals -- water fleas, mosquito wigglers, worms, tadpoles, and even young fish -- which they grab with a long jointed lower lip that has a spoon-like tip, Still more strange, they are jet- propelled. They can fold their legs and dart forward by squirting water from the gill chamber that fills most of the abdomen. The damselfly nymphs, on the other hand, are more slender, have grasping jaws, and have three oar-like gills on the tail end which enable them to swim like fish.

The high-flying Big Green Darner has a bright green head and thorax, and a four-inch wingspread. It is our largest common dragonfly and the "devil's darning needle" that is supposed to sew up the ears of boys who play hooky. Locally, we have smaller species called Amber Wing, White Tail and Ten Spot, that skim the surface of the water. Some of our damselflies are named Bluet, Ruby Spot and Black Wing but youngsters call them all "snake doctors" or "snake feeders".

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