CLASSIFICATION OF INSECTS. 253 



move horizontally ; the telum is armed with setae, 

 and the body covered with hairs or scales. This 

 class contains two orders. 



824. Lepismites (Lepismites). Antennae very 

 long, composed of a great number of joints, often 

 more than forty ; the telum is furnished with 

 three long setae, composed, like the antennae, of 

 many joints ; it is not capable of being bent under 

 the insect. Forbicina, Petrobius, Lepisma. 



825. Spring-tails (Podurites). Antennae shorter, 

 never apparently composed of more than four 

 joints, although the last has numerous rings, which 

 may, perhaps, be considered joints by some : the 

 telum is furnished with two setae, and is bent 

 under the body, giving an amazing saltatory 

 power to the insect. Podura, Smynthurus. 



826. In the second class (Anoplura) the mouth 

 appears very imperfect; in one order there are 

 mandibles with an horizontal motion, in the other, 

 they are elongate, rigid, and united ; the telum is 

 not furnished with appendages. The insects com- 

 posing the class are entirely parasitical on other 

 animals. This class contains two orders. 



827. Lice (Pediculites). Mouth with the 

 mandibles and other parts united, and forming a 

 short blood-sucking tube : the animals composing 

 this order are found on the bodies of mankind, 

 dogs, pigs, cattle, &c. Phthirus, Pediculus, 

 Haematopinus. 



828. Biid-ttce (Nirmites). Mouth with distinct 



