196 FORMICARIIDA. 
b!. Rostrum compressum. 
THAMNOPHILUS. 
Thamnophilus, Vieill. Anal. p. 40 (1816) ; Scl. Cat. Birds Brit. Mus. xv. p. 180. 
Thamnophilus is by far the largest genus of the F ormicariide, containing between 
sixty and seventy species, according to Mr. Sclater, of which fifty-five were more or less 
known to him. ‘These are distributed over the whole area of the family, which is 
represented both in the extreme northern and southern limits by members of the 
genus. In Mexico and Central America nine species occur, of which two only reach 
Southern Mexico and Guatemala, the rest all belong to the southern section of our 
fauna. 
Mr. Sclater divides Thamnophilus into six sections, basing their characters upon size 
and the colour of their plumage. 
The first Section A, represented by the great 7’. Jeachi, is not found within our area, 
but the other five sections are all present. 
Whether all these sections should be merged under Thamnophilus is a doubtful 
question, a revision of them would probably result in the recognition of several genera. 
For them many names are available, proposed at various times, chiefly by Reichenbach 
and by Cabanis and Heine. JT. doliatus is usually considered the type of Thamno- 
philus. Its plumage is soft and lax, the bill smooth, the culmen slightly curved till 
it descends rather abruptly to a well-marked but not very prominent hook, before 
which, at the end of the tomia, is a moderately deep notch; the tomia of the mandible 
has also a small subterminal notch; the tomia of both maxilla and mandible is nearly 
straight, but the gonys of the latter ascends in a gradual curve; the tarsi have well- 
defined scutella, both in front and behind; the claws are short and curved, and have 
deep grooves on both inner and outer lateral surfaces. ‘The tail is moderate and rounded, 
and the wings short and rounded, the fourth to the eighth primaries subequal, third= 
tenth, the first much the shortest, the second halfway between the first and third. 
T. melanocrissus, belonging to Mr. Sclater’s Section B, has much less soft plumage, 
the bill is more compressed, larger in proportion, and with the terminal hook and sub- 
terminal notches well developed ; the wings are similarly shaped to those of 7’. doliatus, 
but the tail is longer in proportion. The colour of the plumage is pure white beneath, 
black above in the male, brown in the female. 7. bridgesi of Section D, besides its 
differently coloured plumage, has a differently shaped wing, the second primary being 
much longer than in 7. doliatus, falling little short of the third and fifth, and the 
fourth the longest in the wing ; the tail, too, is longer in proportion to the wing than 
that of 7. doliatus. T. atrinucha (Section D) has soft plumage like J. doliatus, but 
differs chiefly in its style of colour being grey and black, but without transverse bars; 
the male, too, has the white concealed dorsal spot so frequently present in other Formi- 
cariide. T'. punctatus, a representative of Section C, has plumage like that of 
