Any one of numerous species of small apterous insects belonging to the order Thysanura. They have two elastic caudal stylets which can be bent under the abdomen and then suddenly extended like a spring, thus enabling them to leap to a considerable distance. See Collembola, and Podura.

any of numerous minute wingless primitive insects possessing a special abdominal appendage that allows the characteristic nearly perpetual springing pattern; found in soil rich in organic debris or on the surface of snow or water

Springtails (Order Collembola) form the largest of the three orders of modern hexapods that are no longer considered to be insects (along with the Protura and Diplura). The three orders are sometimes grouped together in a class called Entognatha because they have internal mouthparts, but they do not appear to be more closely related to one another than they are to the insects, which have external mouthparts. Recent genetic studies suggest that the Collembola are a separate evolutionary line from the other Hexapoda .