XI 



THE WATER SPRING-TAIL 



365 



soon as the stick was taken away. They were only 

 one twelfth of an inch long, and entirely black. The 

 body was cylindrical, divided into segments, and 

 tapering sharply at the hinder end. The head 

 carried a pair of short, mobile, four-jointed antennae 

 and a number of simple eyes. The legs were short, 

 and ended in single claws. The tail, as De Geer 

 very naturally calls the forked appendage, could be 

 bent forwards beneath the body, 

 and then, being forcibly ex- 

 tended, could throw the Insect 

 like a skip-jack into the air. 

 De Geer remarks that the spring 

 remained extended for a little 

 while after the Insect alighted, 

 and was then gently drawn for- 

 wards. The act of leaping 

 seemed to him clumsily per- 

 formed, for the Podura generally 

 fell on its back, and wriggled 

 about to regain its natural 

 position. When undisturbed, it 

 moved on the surface of the 

 water by a slow creeping action. 



White specks were seen floating on the water 

 among the black masses, and these De Geer found 

 to be cast skins of the Podura. 



De Geer gives a clear figure of the forked spring, 

 and notices also a little rounded prominence between 

 its branches. This is now considered to be an organ 

 of adhesion, and De Geer himself so describes it at 

 a later time in another Thysanuran. Many of the 



Fig. III. — Podura aquatica. 

 X 30. From Lubbock. 



