324 COMPARATIVE ZOOLOGY. 
peckers are assisted by their stiff tail, and the Parrots by 
their hooked bill. The important Scansores are the Par- 
Fig. 312.—Head of a Fly-catcher (Tyrannus). 
rots, Woodpeckers, Barbets, Toucans, Cuckoos, Jacamars, 
and Trogons. 
10. Jnsessores, or Perchers.—This order is the most nu- 
merous and varied in the whole class. It comprehends all 
those tribes which live habitually among trees, excepting 
Fig. 313.—Goat-sucker (Caprimulgus). 
