DESCRIPTION AND CLASSIFICATION OF INSECTS. 37 



60. Another family of those insects are appropriately named 

 bird lice, from the animals on which they are found. Every 

 farmer is familiar with the parasitical insects found on sheep, 

 dogs, horses, oxen, &c. 



The gnawing louse infecting the sheep (Trichodectes sphoe- 

 rocephalus) destroy the wool by cutting it near the root. The 

 ox is attacked by two kinds of lice, one being a sucking and the 

 other a gnawing insect. Indeed, it may be said generally that 

 every species of quadruped is inhabited by one or more species 

 of the louse tribe. 



