1911 Encyclopædia Britannica/Springtail

SPRINGTAIL, the common name of a group of small insects, so named from the presence of a pair of tail-like appendages at the end of the abdomen, which acts as a spring. When the insect is undisturbed these appendages are turned forwards and held in position by a catch beneath the abdomen; but in case of alarm they are kicked forcibly downwards and backwards, jerking the body into the air. This action may be rapidly repeated until a place of safety is reached. These insects usually live under fallen leaves, stones or the bark of trees, and sometimes occur in such quantities as to resemble patches of powder or dust. One species (Podura aquatica) may be seen floating in this way in masses upon the surface of standing water. Another (Achorutes socialis) may sometimes be found in abundance in the snow. Zoologically the springtails belong to the sub-order Collembola of the order Aptera (q.v.).