622 BULLETIN 5 0, UNITED STATES NATIONAL MUSEUM 



jugger) or both first and second distinctly emarginated {F. mexicanus), 

 the second and third with outer webs sinuated (in all species). Tail 

 about half as long as wing {F. biarmicus) to decidedly more than half 

 as long {F. jugger, F. mexicanus), slightly but distinctly rounded, the 

 graduation about equal to length (chord) of culmen (decidedly less in 

 F. biarmicus), the rectrices (12) appreciably narrower terminally (espe- 

 cially middle pair). Tarsus about one-third to one-fourth as long as 

 tail, rather stout, covered with small roundish scales (these somewhat 

 larger on anterior portion of inner side), the upper portion feathered 

 in front and on sides for between one-third and one-half the total 

 length; middle toe, without claw, decidedly shorter than tarsus; outer 

 toe (without claw) decidedly shorter than inner, the latter (without 

 claw) reaching to penultimate articulation^of S middle >; toe; 'hallux 

 decidedly longer than basal phalanx of middle toe, its claw decidedly 

 shorter than the digit. 



Plumage and coloration. — Plumage very compact, the remiges and 

 rectrices rigid, the feathers of upperparts very distinctly outlined; 

 orbits completely bare, the cere almost entirely so ; thigh-plumes well 

 developed. Head with a more or less conspicuous "mustache," 

 originating at rictus and extending obliquely across malar region to 

 sides of thi'oat, and with a more-or-less broad postocular stripe or 

 streak; adult male usually more-or-less barred above (except on pileum 

 and primaries), the underparts vv^hite, buffy, or pale vinaceous, more 

 or less spotted and streaked with dusky; adult females and young 

 grayish brown above not distinctly if at all barred, the wing coverts, 

 scapulars, and interscapulars margined with rusty or buffy. 



Range.— Open or treeless districts, southern Europe and northern 

 central Africa to India, Mongolia, etc.; one species in western North 

 America. (Several species.) 



F. mexicanus does not agree entirely in details of external structure 

 with the type of the subgenus, which has only the first (outermost) 

 primary with inner web emarginated, instead of the first and second, 

 and the fii'st primary equal to the third instead of the fourth. The 

 tail is relatively longer in F. mexicanus, but not more so than in F. 

 jugger, which, in the emargination and relative length of the primaries 

 agrees with F. biarmicus. Notwithstanding these dift'erences, how- 

 ever, the points of resemblance (even to coloration) are so numerous 

 that the separation of F. mexicanus would, in my opinion, be unneces- 

 sary. Except in coloration of the head, the adult males of F. mexicanus 

 and F. biarmicus resemble each other very closely. 



