IgO REVIEW OF AMERICAN BIRDS. [PART I. 



Family SYLYIC0LID^.» 



The Syli-icoUdse are essentially characterized among the Oscines 

 with nine primaries," by their small size, the i>sually slender and 

 conical insectivorous bill, shorter than the 4iead, without angle in 

 the gape near the base ; the toes deeply cleft so as to leave the inner 

 one free almost to its very base (except in Mniotiltese), etc. The 

 shallow notch at the end of the tongue, instead of a deeply fissured tip, 

 distinguishes the family from the Gserehidse, to some of which there 

 is otherwise so great a resemblance. The absence of abrupt hook 



• A diagnostic table of families will be given as an appendix to the work. 



* Although we speak of the absence of the outer or first primary, and the 

 presence of nine only as characterizing most of the Oscines, the expression is 

 not strictly correct, as in all cases where I have made a careful search, I have 

 never failed to find the first primary in a rudimentary condition. Indeed 

 the gradation from the very short, though evident spurious primary of some 

 of the Vireos, to the stage in others of the genus where this primary appears 

 entirely wanting, is merely the diflerence between its being placed so as to rest 

 on the inner side of the basal portion of the shaft of the outer large feather 

 or moved round so as to lie on its outer side. It occupies the terminal 

 joint of the wing, just as when well developed, and is only overlooked be- 

 cause confounded with the coverts of the primaries. Its presence can easily 

 be demonstrated by comparing the wing of a Thrush, with distinct first pri- 

 mary, and that of a Sparrow, Swallow, or other bird, in which this primary is 

 wanting (very well seen in Qaiscalus). In the Thrush, for instance, there will 

 be seen the usual coverts on the outside of the primaries, each one with its 

 sheath inserted into that of the corresponding primary, and resting a little on 

 the external side of the barrel of the quill. The first quill lacks a covert ; 

 all the rest, nine in number, have one each. The first covert is usually much 

 shorter than the rest, and stands singly when there is a distinct, though 

 abbreviated first primary, as in Titrdus. In a Sparrow, however, or Quisralus, 

 there appears to be a second short covert, immediately beneath the one just 

 referred to, but which, on examination, is seen to occupy the true place of the 

 deficient first primary. Whenever, therefore, there are apparently only nine 

 primaries, it is probable that two of these short stiff feathers will be found, 

 and with ten distinct primaries only one will be found. When there is any 

 peculiar coloration of the primaries, not seen in the other feathers of the 

 wing, this second of the short feathers will have it, and not the outside one, 

 as will be referred to more particularly hereafter, especially under Vireo 

 flnrifrons. 



