Passerine Birds 259 
b* Tail-feathers normal. 
a® Bill slender, as long as the head; tail shorter than 
the wing. Sittide, p. 498. 
b> Bill stout, shorter than the head; tail equal to 
or longer than the wing. Paride, p. 503. 
bi Tarsus booted, not divided into plates except at the extreme 
base. 
a? No rictal bristles; tail abnormally short. 
Cinclidz, p. 474. 
b? Rictal bristles present ; tail normal. 
a? Small; wing under 3-0; plumage greenish; young 
not spotted. Sylviidz (Regulus), p. 509. 
b? Larger, wing over 3-0; young spotted. 
Turdide, p. 514, 
Family TYRANNID. 
Bill broad, depressed and flat, the tip down-turned ; 
nostrils not operculate ; wings with ten primaries, the 
outer one of which is always well developed and obvious ; 
tail of twelve rectrices usually even or nearly so; feet 
small and weak, tarsus excapedian, i.e. covered with 
variously arranged scutes, not forming a ridge at the 
posterior edge, but meeting on the postero-internal face 
in a deep groove. 
Six of the twelve North American genera are found 
in Colorado. They can be distinguished as follows* :— 
A. Tips of the outer primaries attenuated; a concealed crown- 
patch of orange. Tyrannus, p. 260. 
B. Tips of the outer primaries not attenuated ; no crown-patch. 
a. Tail marked with rufous; a distinct crest. Myiarchus, p, 264. 
b. Tail plain coloured without rufous; no distinct crest. 
ai Feet very small; tarsus not exceeding the culmen in length. 
a* Tail very short, less than % length of wing; a patch 
of silky feathers on either side of the rump. 
Nuttallornis, p. 268. 
b? Tail longer, about } length of wing; no silky patch 
on rump. Myiochanes, p, 270. 
* Muscivora forficata, the Scissors-tailed Flycatcher, is included_by Cooke in the 
Colorado avifauna on the strength of it havng been once seen by G. F. Brenninger at 
Table Rock, on the Arkansas-Platte divide. 9 
Ss 
