CLASS INSECTS, 



411 



nine may be counted, and when there are fewer it seems as if 

 some had become fused. In the perfect insect, these rings or 

 segments have neither wings nor limbs ; but those occupying 

 the posterior extremity of the body give origin to appendages 

 varying both in form and size. Sometimes they are simple 



Fig. 428. Conops. 



hairs or stylets, whose functions are not well known, as in 

 the ephemera, for example (Fig. 458). Sometimes these 

 organs affect the forms of hooks, and constitute more or less 

 powerful forceps, as in the forficula or earwig (Fig. 429). 



Fig. 429. Forficula ; 

 Earwig. 



Fig. 430. Podurella ; 

 Skiptail. 



Sometimes they answer the purpose of a spring, to enable the 

 animal to move forward, as in the podurella (Fig. 430), 

 small insects, which in our climate conceal themselves under 

 the stones, or float to the surface of stagnant waters, and 

 which are sometimes found under the snow in the coldest 



