BASILEUTERUS. 173 
In 1873 the Costa-Rica form of this Basileuterus was separated from B. uropygialis 
under the name of B. leucopygius!, as it was then thought to be sufficiently different 
from the Panama bird to warrant the distinction, A reexamination of the types now 
convinces us that one of the chief differences relied upon, the pale colour of the rump, 
is due to the worn and faded state of the specimens; so that we are driven to the 
conclusion that the Costa-Rica and Panama birds belong to the same species. For 
this we retain the somewhat inappropriate name Basileuterus leucopygius, for the 
reasons stated below. 
This bird was first known as an inhabitant of Central America from specimens 
obtained by M‘Leannan and Galbraith 2. These were called B. semicervinus of Sclater 
by Mr. Lawrence, an identification that was subsequently questioned, as the birds were 
supposed to agree better with B. uropygialis of the same author ®, As some confusion 
exists relative to these two species, we propose briefly to examine them. 
The description of B. semicervinus was based upon specimens obtained near Nanegal 
in Western Ecuador by Fraser*. We have since received examples from Santa Rita, 
on the same side of the Andes of Ecuador; and we have also others, of Salmon’s 
collecting, from Remedios in the Cauca valley, Colombia, which are correctly referred 
to B. semicervinus +. It would thus appear that B. semicervinus is a bird of Western 
Ecuador, extending northwards, as is so frequently the case in birds of that district, into 
the Cauca valley. 
Basileuterus uropygialis was described from a specimen with the vague locality 
“ Brazil” attached to itt. ‘This bird we now recognize in specimens from Sarayacu in 
Eastern Ecuador, Chyavetas in Peru, and Bogota, the latter probably obtained in the 
upper valley of the Meta. Thus it appears that each of these birds has a very distinct 
range, separated by the Andes. Their differences are described in, and both birds are 
figured on a plate accompanying, a synopsis of the species of Basileuterus, published by 
Mr. Sclater in 1865||. It will there be seen that B. semicervinus has a darker back, 
and the underparts strongly tinged with fawn-colour, whereas B. wropygialis has an 
olive back, and usually pale underparts. 
Now, on reconsidering the position of the Central-American bird, we are of opinion 
that it comes nearest to the bird of Western Ecuador, B. semicervinus, rather than that 
of the upper valleys of the basin of the Amazons, B. uropygialis. 
But as the present bird has the feathers of the breast more or less edged with brown, 
and the sides of the neck and flanks not nearly so clear a fawn-colour as in B. semi- 
cervinus, but decidedly browner, we keep B. leucopygius under a distinct name. At 
the same time we admit that the relationship with B. semicervinus is very close, and 
recognize the justice of Mr. Lawrence’s first application of this name to the Panama 
bird. 
* Scl. P. Z. 8. 1860, p. 84. T Sel. & Salv. P. Z. 8. 1879, p. 494. f Sel. P. Z.S. 1861, p. 128, 
§ Scl. & Salv. P. Z. 8. 1873, p. 257, || P.Z. 8. 1865, p. 282 ed seq., t. 10. 
