316 ZOOLOGY. 



i'ng as are the others, by which character the birds of this order may at 

 once be distinguished from any of the others, except the Scansores, in 

 which, however, the arrangement of the toes in pairs is so pecuhar that no 

 chance of confusion exists. 



The food of the Passeres consists principally of fruits or seeds and 

 insects, the greater part of the species being omnivorous, or eating indis- 

 criminately almost any description of these two classes of food which can 

 be most readily obtained. There are many genera, however, the food of 

 which is exclusively insects, and many others which never or rarely eat 

 anything else than seeds ; and others, again, which subsist almost entirely 

 upon the pulp of fruits. All these, however, admit of classification, and 

 will be regarded by us as constituting sub-orders or tribes. 



The larynx, or organ of voice, is generally of complex structure in the 

 birds of this order, which contains all that are commonly known as singing 

 birds. There are few species which do not either sing or utter notes more 

 or less musical, especially during the season of courtship ; and even of those 

 whose voices are harsh, some are frequently capable of being taught to 

 imitate other sounds. 



In this order the female is very generally smaller and less brilliant in her 

 plumage than the male. They usually live in pairs, build mostly in trees, 

 and frequently display great art in the construction of their nests. 



We shall divide this extensive order into four sub-orders or tribes, 

 viz. : FissiRosTREs, or split-billed birds, Tenuirostres, or slender-billed, 

 Dentiro.stres, or birds with toothed bills, and Conirostres, or conic-billed 

 birds. 



Sub-Order 1. Fissirostres, 



This is comparatively a small group when compared with the extensive 

 sub-orders of Dentirostres and Conirostres. It comprises all the birds com- 

 monly known by the names of Swallows, Night-hawks, Kingfishers, Tro- 

 gons, Bee-eaters, and some others of similar general characters. 



The Fissirostres are generally distinguished by having the powers of 

 flight developed to the highest degree. The beak is usually short, broad, 

 and very deeply cleft, so that the opening of the mouth is very v;ide, or, 

 as some of the old writers express it, they are very big in the swallow. 

 Possessing this kind of bill they are adapted to capturing insects on the 

 wing, receiving them into their mouths while in full flight. There are, 

 however, some genera in which the characters of this group are not so 

 strongly marked, and in which the bill is longer and stronger and the flight 

 not so rapid nor long continued, but they all have the characteristic wide 

 mouth. 



These birds subsist almost entirely upon winged insects. 



Fam. 1. HiRUNDiNiD^, OR SwALLows. Bill Small, much depressed, some- 

 what triangular ; wings mostly very long, curved ; tail various, frequently 

 long and forked, sometimes short and truncate. Plumage compact, glossy; 

 size small. 



No birds are more universally or more favorably known than the 

 swallows. Distributed through the entire globe, and usually conspicuous 



