FORMICARIIDA. 193 
Fam. FORMICARIIDA. 
In Mr. Sclater’s recently published catalogue of this family (Cat. Birds Brit. Mus. 
xv. pp. 176-328) we find the names of 254 species given in the body of the work, and, 
in addition to these, 87 other names are mentioned in footnotes as belonging to birds 
with which the author was not acquainted. The total number of species in the family, 
therefore, may be taken at about 500. Of these 52 occur within our limits, belonging 
to 19 genera. By far the larger proportion cf these species belong to the southern 
section of our fauna, 7. é. that lying between Nicaragua and the Isthmus of Darien. 
In the more northern section the number of species rapidly diminishes until we find 
but a single species, Thamnophilus doliatus, ranging beyond the State of Vera Cruz, 
and none on the western side of Mexico beyond the State of Guerrero. The same 
diminution of numbers is found towards the southern limit of the range of the family, 
only four species being found in the Argentine Republic. A great concentration of 
species takes place in the Amazons Valley, especially in the upper or western portion 
of that vast district; Guiana, too, is very rich. 
Regarding the classification of the Formicariide, we are met with the same diffi- 
culties that we encountered when dealing with the Dendrocolaptide and some of the 
preceding families, and this chiefly affects the recognition of subfamilies. 
Though we adhere pretty nearly to the sequence of the genera as set forth in Mr. 
Sclater’s recently published system, and we also divide the family into two main groups, 
we arrange the genera under these sections differently and define them by different 
characters. One of these sections contains the tree and bush frequenting genera, most 
ot which have comparatively short tarsi. The other contains the terrestrial birds, 
some of which (comprised in the genera Gymmnopithys, Gymnocichla, Myrmeciza, 
Hypocnemis, &c.) follow the hordes of foraging ants (Eciton) and feed on the insects 
started from their path. The others are more solitary in their habits, and are usually 
found singly on the ground in the deepest parts of the forest. We have used small 
characters which fairly define these groups, but our knowledge of the habits of these 
birds and of their internal structure is so fragmentary that many modifications of their 
arrangement will have to be made before a settled system is established. 
Of the nests and eggs of the members of this family little is yet known, and we are 
chiefly indebted to the late T. K. Salmon for the scanty knowledge we possess. From 
his notes we gather that probably all the species make their nests in trees or bushes, 
and this applies even to the birds that pass most of their time on the ground. The 
nests are often hanging structures, suspended in a forked branch near the extremity of 
a bough. ‘The eggs are very varied, some being white (Myrmotherula), some white and 
thickly spotted (Zhamnophilus), some creamy white sparsely spotted (Dysithamnus), 
BIOL. CENTR.-AMER., Aves, Vol. IL., February 1892. 25 
ae 
