Nepidae is a family of exclusively aquatic Heteropteran insects commonly called water scorpions for their superficial resemblance to scorpions. They have raptorial forelegs and a long slender proboscis at the posterior end of the abdomen, resembling a tail, which can be thrust above the surface of the water and used as a breathing tube.

Insects can be found on every continent ... but just barely. The only true insect on the southernmost continent is a wingless midge called Belgica antarctica. The tiny fly is only 0.08 to 0.23 inches (0.2 to 0.58 centimeters) long, but it's still the Antarctic's largest terrestrial animal.

The life span of most insects is very short, sometimes only a few days, but for some African species of termites, a queen's life span may be up to 50 years.

Most insects undergo a four-stage metamorphosis over the course of a lifetime. Each stage of the life cycle--egg, larva, pupa, and adult--is marked by a distinctly different appearance, habitat, and food source.

The bullet ant's sting is currently the highest on Schmidt's sting pain index, at 4.0+. Some victims compare the pain to that of being shot, hence the name of the insect. "With a bullet ant sting, the pain is throughout your whole body," adventurer and naturalist Steve Backshall explained on an episode of BBC's Infinite Monkey Cage. "You start shaking, you start sweating, your heart rate goes up, and if you have quite a few of them, you will be passing in and out of consciousness. There will be nothing in your world apart from pain for at least three or four hours."

The word "insect" comes from the Latin word insectum, meaning "with a notched or divided body", or literally "cut into" because insects appear "cut into" three sections: head, thorax, and abdomen.

Fairyflies are some of the most common chalcid wasps but are rarely noticed by humans because of their extremely small size. In fact, fairyflies are nearly 400 times smaller than the typical ant--about two or three times the width of a human hair.

Most popular textbooks mention "giant dragonflies" that lived during the days before the dinosaurs, but this is only partly true as real dragonflies hadn't evolved yet. Primitive griffinflies or Meganisopterans had wingspans that could reach 28 inches. The largest of these fossils were found in France and Kansas and were 300 million to 280 million years old.

The German cockroach reproduces faster than any other residential cockroach, growing from egg to reproductive adult in roughly 50 to 60 days. One female and her offspring can infest a home with more than 30,000 cockroaches in just a single year.

Moths don't waste time once they reach adulthood. They emerge from their cocoons ready to mate and die soon afterward. Since they won't be around for very long, they can get by on the energy they stored as caterpillars. Many species, like the Luna, Polyphemus, Atlas, and Promethea, don't even have mouth parts.