20-1 



Following then nearly the arrangement of Bnrmeister, already 

 alluded to, we can separate the Formicariida into three divisions, 

 which, although some of the genera in each are rather forms of 

 transition from oue to the other, may, I think, be most conveniently 

 regarded as so many subfamilies. The first of these, the Thamno- 

 philince, contains the largest and strongest birds of the group ; and it 

 is easy to conceive that a writer unacquainted with the intermediate 

 links which bind Batara cinerea and other strongly formed species 

 to their " weaker brethren," would at the first sight of the formi- 

 dable bill be inclined to locate them among the Laniidce. But the 

 graduated series that connects these with the more typical Formica- 

 rians follows in a succession so regular that the real difficulty is rather 

 to decide where the most salient breaks occur, and where one genus 

 ends and the next begins. The Thamnophilince are characterized 

 by their strong, deep, and compressed bill, which is hooked at the 

 tip and notched ; their short rounded wings ; their long, broad-fea- 

 thered, much-rounded tail, and strongly formed feet, with the tarsi 

 rather elongated, and both the acrotarsia and the paratarsia divided, 

 and the outer toe showing some signs of conjunction with the 

 middle. The sexes of the birds of this division are always of very 

 different colours, the males being varied with black and white, the 

 females with brown. In the second subfamily — the Formicivorincc 

 — we find a series of smaller and more feebly formed species, which 

 are appropriately denominated by Swainson Ant-wrens. These have 

 the bill much more slender, not usually compressed, but as broad as 

 it is deep, and often much elongated ; the tip of the upper man- 

 dible is but very slightly hooked, and the final tooth often nearly 

 obsolete. The wings are short and rounded. The tail varies much, 

 being in some genera very long, and in others extremely short. The 

 tarsi are much more slender than in the Thamnophilines ; the outer 

 toe rather more closely connected with the middle. The sexes are 

 (with but few exceptions) different, as in the Thamnophilince. The 

 members of the third subfamily, or Formicariince, are more Thrush- 

 like in appearance, and are, again, more strongly formed but en- 

 tirely terrestrial species, whence they are named by D'Orbigny 

 " Fourmilliers marcheurs," or Ambulatores. In accordance with 

 these habits, the tarsi are much lengthened* the feet rather large, 

 and the toes long. The tail is always short and small, and nearly 

 square at the termination. The wings are short as before. The 

 bill is rather variable, being in some genera broad, in others rather 

 thick and strong. The sexes of these birds are usually coloured alike. 

 In life, I believe, they carry their tail upright or even inclined 

 forwards, like the Wrens, in which respect, as in general conforma- 

 tion, they much resemble the birds of the nearly allied family 

 Pteroptochidce. 



The Formicariidce are a strictly Neotropical group, occupying the 

 same area as the Cotingidce, the Momotidce, the Galbulidce and 

 other characteristic families of this fauna. The most northern loca- 

 lity in which I have ascertained their occurrence is in the State of 

 Vera Cruz, in the tierra caliente of Mexico, where M. Salle found 



