Bristletails: Microcoryphia

Bristletails are true insects that never develop wings. They have young that look just like the adults. Their mouthparts, unlike those of diplurans, proturans, and collembolans, are not hidden inside a pocket in the head. They range in size from 0.3 to 0.8 inches (7 to 20 millimeters), not including their tails. The thorax, or midsection, is divided into three sections, each with enlarged upper and lower plates, giving the bristletail a humpback or teardrop shape. The entire body (head, thorax, and abdomen) is covered with flat scales. The head has a pair of long, threadlike antennae (an-TEH-nee), or feelers, and long, leglike mouthparts that look much like a fourth pair of legs. The large eyes consist of many lenses.

The ten-segmented abdomen is tipped with three long, bristlelike tails that are held straight out from the body. All but the first abdominal segments have paired structures underneath that help support the abdomen and keep it from dragging on the ground. Most of the abdominal segments usually have special sacs underneath that help attach the bristletail to the ground so that it can molt, or shed its external skeleton.