PASSERES : THRUSHES, ETC. 153 



SUB-SECTION II. 

 THE ORDER OF PASSERES OR INSESSORES. 



THE name Passeres comes from the Latin passer, a 

 sparrow ; and the name Insessores from the Latin in- 

 sideo, to perch. The latter of these names is used by 

 some ornithologists to designate a sub-class of birds, 



tr> i * 



namely the Aerial Birds, including the old groups Rap- 

 tores, Scansores, and Insessores. By others the name In- 

 sessores is used as essentially equivalent to Passeres ; and 

 in this latter sense we prefer to use it for our present 

 purposes. 



The Passeres, by the nature of their feet, are perfectly 

 adapted for perching, the four toes being always present, 



FIG. 1G8. 



A Passerine or Insessorial Bird, Wood Thrush, Turdus musldinus, Gmelin. 



the hind toe inserted on nearly the same level as the others, 

 and perfectly opposite to the forward toes. 



The Passeres have a horny bill ; wings with nine or ten 

 primaries, and more- than six secondaries ; and in most 

 cases they have twelve tail feathers. 



