258 Birds of Colorado 
b? Head not crested. 
a* Inner secondaries elongated, nearly as long as the 
longer primaries; hind claw straight, equal to or 
exceeding the hind toe. Motacillidz, p. 472. 
b4 Inner secondaries not elongated, hind claw curved, 
always clearly shorter than the hind toe. 
Mniotiltidez, p. 438. 
b? Bill short, stout, deep and conical. 
a? Bill notched at the tip and with bristles at the gape. 
a‘ Nostrils more or less concealed by bristles or overhung 
by a distinct scale, or the cutting-edge of the lower 
mandible forming a distinct angle. 
Fringillide, p, 319. 
bt Nostrils exposed ; cutting-edge of the lower mandible 
always straight and without any angle. 
Tangaride, p. 408. 
b? Bill without notch at the tip, or bristles at the gape. 
. Icteridz, p. 299. 
b. Primaries obviously ten; the outer one more or less shortened. 
al Tarsus distinctly scutellate in front. 
a* Outer primary at least half as long as the next. 
a’ Bill distinctly hooked at the tip. Laniide, p. 427. 
b? Bill not distinctly hooked at the tip. 
a4 Nasal plumes erect or inclined backwards. 
a> Rictal bristles well developed. 
Mimidz (except Oroscoptes), p. 477. 
b® No rictal bristles. Troglodytide, p. 485. 
bt Nasal bristles directed forwards and nostrils con- 
cealed. Corvide, p. 282. 
b? Outer primary not half as long as the next, generally 
much shorter. 
a’ Bill slightly hooked or notched at the tip. 
at Smaller; wing under 2-5. 
a’ Above greenish or greyish; tail even. 
Vireonide, p. 431. 
b> Above bluish, tail graduated. 
Sylviidz (Polioptila), p, 509. 
b‘ Larger, wing over 3-5. 
Mimidze (Oroscoptes), p. 477. 
b?_ Bill not hooked or notched. 
a‘ Tail-feathers stiff and pointed at tip. 
Certhiidz, p. 496, 
